Optical Deflector Drive Timing for Stable Offset and Amplitude Changes
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Solution Overview
Problem
Existing optical deflector systems experience abnormal oscillation and striped patterns in the pictures drawn by light scanning due to unintended frequency components in the driving signal waveform when changes in offset or amplitude are reflected.
Innovation Solution
The optical deflector system employs a configuration with piezoelectric cantilevers arranged in a bellows shape, applying different driving voltages to even and odd-numbered cantilevers to prevent abnormal oscillation by reflecting changes in offset or amplitude at a determined minimum voltage timing, and optionally includes an offset division unit for stepwise change reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If change in offset or amplitude is reflected at the timing when instruction to change is input, then the system responds quickly to control changes, but abnormal oscillation occurs in the optical deflector and striped patterns appear in the picture
Solution Approach 1:
The system determines the timing when the voltage of the driving signal becomes minimum before reflecting the change. This preliminary timing determination avoids applying the change at inconvenient moments (when voltage is high or changing rapidly), thereby preventing abnormal oscillation while still achieving timely response to control changes.
2Adaptability or versatility
If change in offset or amplitude is reflected, then the picture position or size can be adjusted, but unintended frequency components are introduced causing abnormal oscillation
Solution Approach 1:
The system preliminarily determines the minimum voltage timing before reflecting the change in offset or amplitude. By waiting until the voltage reaches its minimum point, the system introduces changes when the system is most stable and least sensitive to frequency disturbances, thereby avoiding generation of unintended frequency components that would cause abnormal oscillation.
3Productivity
If driving signal voltage is applied to piezoelectric cantilevers to swing the mirror portion, then optical scanning is achieved, but abnormal oscillation occurs when offset or amplitude changes are reflected
Solution Approach 1:
The system preliminarily determines when the driving signal voltage reaches its minimum value before applying offset or amplitude changes. This timing selection ensures that changes are applied when the optical scanning system is in a stable state (low voltage condition), preventing the introduction of frequency components that would trigger abnormal oscillation during the scanning operation.
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 effectively prevents abnormal oscillation and striped patterns by removing unintended frequency components, ensuring stable picture drawing even with offset or amplitude changes.
Implementation Method 1
a plurality of piezoelectric cantilevers disposed in a direction of the swing axis. The plurality of piezoelectric cantilevers are coupled in a bellows shape to cause each of the piezoelectric cantilevers to be folded back relative to an adjacent piezoelectric cantilever
Data Source
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Figure 3A
AI summary
There are provided an optical deflector driving system and the like that can prevent occurrence of abnormal oscillation in an optical deflector even in a case where change in offset (or amplitude) is reflected. An optical deflector driving method includes: a change instruction input step (S20) of inputting an instruction to change at least one of a first driving signal corresponding to a first driving voltage and a second driving signal corresponding to a second driving voltage, the first driving voltage and the second driving voltage being applied to an actuator swinging a mirror portion of an optical deflector around a swing axis; a determination step (S21 and S23) of determining, in a case where the instruction is input, a timing when a voltage of a driving signal to be changed out of the first driving signal and the second driving signal becomes minimum; and a change reflection step (S25 and S27) of reflecting, in a case where it is determined that the timing when the voltage of the driving signal to be changed becomes minimum comes, the change on the driving signal to be changed.