Mirror Scanning Control With Frequency and Temperature Compensation
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Solution Overview
Problem
Existing light scanning apparatuses face challenges in achieving high-precision operation when the mirror is swung in a linear mode with each of the first and second axes as central axes, particularly due to variations in deflection angle and shifts caused by frequency changes and temperature fluctuations.
Innovation Solution
A light scanning system and apparatus that includes a mirror device with drive coils, a magnet, a temperature sensor, and an arithmetic part to generate current signals based on target deflection angles, frequencies, and data to correct for shifts and temperature changes, ensuring precise operation by inputting first and second current signals to the drive coils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the mirror is swung in a linear mode with each of the first axis and the second axis as the central axis, then the light scanning apparatus can perform precise scanning operations, but the deflection angle varies due to frequency changes and temperature fluctuations, reducing measurement precision
Solution Approach 1:
The patent implements feedback control by measuring the actual deflection angle using detection means and comparing it with the target deflection angle. The arithmetic means then adjusts the drive signals based on the difference between actual and target values, ensuring high precision despite frequency changes and temperature fluctuations. This closed-loop feedback mechanism maintains measurement precision while preserving the stability of scanning operations.
Solution Approach 2:
The patent compensates for temperature-induced deflection angle changes by detecting the temperature of the mirror device and arithmetic means. Based on the detected temperature and target deflection angle, the system calculates corrected drive signals that account for thermal expansion and material property changes. This parameter-based compensation ensures precise deflection angle control under varying temperature conditions.
2Measurement precision
If correction data for frequency changes, axis shifts, and temperature effects are stored and processed, then deflection angle precision is improved, but the device complexity increases due to additional sensors, storage, and processing requirements
Solution Approach 1:
The patent combines multiple correction functions into a single integrated arithmetic means that processes frequency correction data, axis shift correction data, and temperature correction data together. The detection means also integrates temperature sensing with the existing deflection angle detection system. This merging approach achieves high precision deflection angle control while minimizing the increase in device complexity by consolidating correction operations into unified processing units.
3Reliability
If multiple correction data sets are stored for different operating conditions, then the light scanning apparatus maintains high precision across varying temperatures and frequencies, but the processing load increases due to real-time data retrieval and calculation
Solution Approach 1:
The patent stores correction data in advance for various frequency values, temperature conditions, and axis shift scenarios. The arithmetic means retrieves the appropriate pre-stored correction data based on current operating conditions and applies it to the drive signals. This preliminary preparation of correction data eliminates the need for complex real-time calculations, reducing processing time while maintaining high precision across varying operating conditions.
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 system enables high-precision operation with errors in deflection angle suppressed to ±0.1° or less, simplifying the system structure and reducing processing load by correcting for individual variations and temperature effects.
Implementation Method 1
a magnet configured to generate a magnetic field to act on a first drive coil provided in the first movable part and a second drive coil provided in the second movable part
Data Source
AI summary
A light scanning system includes a mirror device, a magnet, a temperature sensor, and an arithmetic part. The arithmetic part generates first and second current signals based on a first target deflection angle and a first target frequency, a second target deflection angle and a second target frequency, an operating temperature, first data for correcting a change in a deflection angle of a mirror with respect to a change in a frequency of a current signal input to each of first and second drive coils, second data for correcting at least one of a shift of the mirror swinging with a first axis from a Y-axis and a shift of the mirror swinging with a second axis from an X-axis, and third data for correcting a change in a deflection angle of the mirror with respect to a change in the operating temperature.