Resonant Mirror Light Scanning Control for Laser Safety
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Solution Overview
Problem
Light scanning apparatuses face challenges in non-resonant driving, where the longer cycle length for mirror oscillation increases process time to determine deflection angles, leading to delayed or improper start/stop of laser light output, especially during failures, resulting in potential concentrated laser light emission.
Innovation Solution
A light scanning apparatus that resonantly drives the mirror in the horizontal direction and non-resonantly in the vertical direction, incorporating sensors and control units to estimate deflection angles and change rates, ensuring stable mirror movement and controlled laser light output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If non-resonant driving is used for mirror oscillation, then the mirror can be driven in vertical direction, but the cycle length increases leading to delayed deflection angle determination
Solution Approach 1:
The patent applies preliminary action by determining the deflection angle in advance during the mirror oscillation cycle rather than waiting for the cycle to complete. The deflection angle is calculated based on the drive voltage applied during the oscillation, allowing the system to prepare the laser output timing before the full oscillation cycle finishes, thus reducing the delay in laser start/stop control.
2Productivity
If laser light is output when mirror deflection angle is insufficient, then the scanning function can be maintained, but concentrated laser light emission occurs creating safety hazards
Solution Approach 1:
The patent implements feedback control by continuously monitoring the mirror's deflection angle through sensors and using this information to control the laser output. The deflection angle detection unit provides real-time feedback to the control unit, which adjusts the laser output timing based on the actual mirror position, ensuring laser light is only output when the deflection angle is sufficient to prevent concentrated emission.
Solution Approach 2:
The system performs preliminary determination of the deflection angle before enabling laser output. The control unit waits until the mirror reaches a sufficient deflection angle in the oscillation cycle before initiating laser light output, preventing the harmful concentrated emission while maintaining scanning functionality.
3Duration of action of moving object
If deflection angle determination is delayed, then the mirror oscillation cycle can be completed, but laser light output timing becomes improper during failures
Solution Approach 1:
The patent uses feedback from deflection angle sensors to continuously monitor mirror oscillation status and control laser output timing. This feedback mechanism allows the system to detect failures or abnormal oscillation patterns and adjust laser output accordingly, maintaining reliability even when the full oscillation cycle is not completed.
Solution Approach 2:
The system performs preliminary checks of the deflection angle and oscillation status before enabling laser output. By determining whether the mirror has reached sufficient deflection in advance, the system can prevent improper laser output during failures or abnormal conditions, ensuring reliable 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 approach enables timely and precise control of laser light output, preventing concentrated emission and promoting safety by stabilizing mirror movement and detecting failures quickly, even during non-resonant vertical driving.
Implementation Method 1
a mirror configured to reflect the laser light from the light source
Implementation Method 2
a mirror driving unit configured to resonantly drive the mirror in a first direction
Implementation Method 3
a mirror driving unit configured to resonantly drive the mirror in a first direction and non-resonantly drive the mirror in a second direction
Data Source
AI summary
A light scanning apparatus includes a light source configured to output laser light, and a mirror configured to reflect the laser light from the light source. The light scanning apparatus includes a mirror driving unit configured to resonantly drive the mirror in a first direction and non-resonantly drive the mirror in a second direction, the second direction being perpendicular to the first direction. The light scanning apparatus includes a first sensor configured to output a signal in accordance with a first deflection angle at which the mirror is oriented with respect to the first direction. The light scanning apparatus includes a second sensor configured to output a signal in accordance with a second deflection angle at which the mirror is oriented with respect to the second direction.