MEMS Mirror Irradiation Angle Control via High-Frequency Feedback
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Solution Overview
Problem
The optical space transmission device struggles to sufficiently suppress variations in the irradiation angle of a light beam due to changing resonance frequencies of the MEMS mirror, making it difficult to maintain a consistent beam angle.
Innovation Solution
A light beam irradiation device is designed with a light source, a light reflection unit driven by a signal, a position detection unit that detects the light's position at frequencies higher than the resonance frequency, and a correction unit that adjusts the driving signal based on the detection, allowing for precise control of the irradiation angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the driving signal is supplied to control the deflection angle of the MEMS mirror, then the irradiation angle of the light beam can be set to a desired angle, but the resonance vibration of the MEMS mirror causes variation in the irradiation angle that cannot be sufficiently suppressed
Solution Approach 1:
The patent employs a feedback control mechanism where the position detection unit continuously monitors the light reception position at a frequency equal to or higher than four times the resonance frequency of the light reflection unit. The correction unit then adjusts the driving signal based on detected position variations, creating a closed-loop system that compensates for resonance-induced angle variations in real-time, thereby maintaining stable irradiation angle despite MEMS mirror resonance vibrations
Solution Approach 2:
The patent changes the detection frequency parameter to be equal to or higher than four times the resonance frequency of the light reflection unit. This parameter selection allows the system to capture and correct resonance vibrations effectively, as the high-frequency detection enables the correction unit to generate compensating signals that counteract the resonance effects, thereby suppressing irradiation angle variation
2Measurement precision
If the position detection frequency is increased to follow resonance vibration, then the correction accuracy improves, but the device complexity increases
Solution Approach 1:
The patent implements a dynamic detection and correction system where the position detection unit operates at a variable frequency equal to or higher than four times the resonance frequency of the light reflection unit. This dynamic approach allows the system to adapt to resonance conditions by maintaining detection frequency synchronized with the resonance characteristics, enabling real-time tracking and correction of vibration-induced position variations without requiring overly complex fixed-frequency systems
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 suppresses variations in the irradiation angle, ensuring the light beam is directed at a desired angle with high accuracy by continuously correcting for resonance vibrations.
Implementation Method 1
a light reflection unit including a reflection mirror (21) and a driving unit (24) for swinging the reflection mirror (21) under supply of a driving signal, the light reflection unit receiving and reflecting the light emitted from the light source using the reflection mirror
Implementation Method 2
a position detection unit including a light reception surface (33a) receiving the light reflected by the reflection mirror, the position detection unit detecting a position of the light on the light reception surface
Data Source
AI summary
A light beam irradiation device includes a light source unit that emits a light beam, a reflection mirror and a driving unit that swings the reflection mirror under supply of a driving signal, and comprises the light deflection unit receiving and reflecting the light beam emitted from the light source unit using the reflection mirror, a light deflection angle detection unit that includes a light reception surface that receives the light beam reflected by the reflection mirror, the light deflection angle detection unit detecting a position of the light beam on the light reception surface at a frequency equal to or higher than four times a resonance frequency of the light deflection unit and outputting a detection signal indicating the position, and an operation control unit that corrects the driving signal on the basis of the detection signal and outputs the corrected driving signal to the light deflection unit.