Laser Diode Current Adjustment for Stable Intensity Modulation
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Solution Overview
Problem
Inaccurate control of diode current in laser systems leads to fluctuations in laser power and modulation properties, affecting measurement accuracy and reliability, particularly in environments with temperature and power variations.
Innovation Solution
A method involving a pure I-controller to determine the change in the integral part of the control signal, adjusting the diode current in modulated laser operations, and using digital-analog converters to fine-tune the current based on modulation frequency and system-specific parameters, enabling real-time optimization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional control methods are used for diode current, then the control system is simple, but laser power stability and measurement precision deteriorate
Solution Approach 1:
The patent applies preliminary action by determining the change in the integral part of the control signal during unmodulated laser operation before the actual modulated operation begins. This pre-determined change value is then used to adjust the diode current during modulated operation, improving measurement precision without requiring complex real-time control systems.
Solution Approach 2:
The patent replaces complex mechanical/control system adjustments with a computational approach. Instead of using complex hardware adjustments, the method uses digital calculation to determine the integral part change and applies it through digital-analog conversion, simplifying the physical control system while improving measurement accuracy.
2Stability of the object's composition
If real-time adjustment of diode current is implemented, then laser power stability improves, but processing time and system complexity increase
Solution Approach 1:
The patent performs the complex calculation of the integral part change during unmodulated operation when time is not critical, before the actual measurement begins. This preliminary calculation enables rapid adjustment during modulated operation, achieving laser power stability without sacrificing processing time during the actual measurement phase.
Solution Approach 2:
The patent segments the laser operation into two distinct phases: unmodulated operation for determining the integral part change, and modulated operation for actual measurement. This segmentation allows the system to perform complex adjustments in advance during the first phase, enabling fast and stable operation during the second phase without time loss.
3Measurement precision
If modulation frequency-specific adjustment is applied, then measurement precision improves, but device complexity and calibration requirements increase
Solution Approach 1:
The patent applies local quality by determining the change in the integral part specifically for each modulation frequency used in the laser system. Instead of using a generic control parameter, the method calculates frequency-specific adjustment values that are optimized for each modulation frequency, thereby improving distance measurement precision without requiring overly complex universal calibration procedures.
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
Enhances laser power and stability, allowing for precise and rapid distance measurements with improved accuracy and reliability, especially in laser rangefinders.
Implementation Method 1
The current stimulates the electrons in the active layer and so produces photons, which are then amplified by the laser cavity to generate the laser beam
Implementation Method 2
adjusting the control signal to the digital-analog converter, in particular by determining an offset for an input value of the digital-analog converter
Data Source
AI summary
A method for adjusting a diode current of a laser system includes (i) determining a change in an integral part of a control signal of the laser system in an unmodulated laser operation, and (ii) adjusting the diode current of the laser system in a modulated laser operation based on the determined change in the integral part, wherein the modulated laser operation differs from the unmodulated laser operation in that intensity modulation is performed during light emission in the modulated laser operation. A computer program, an apparatus, and a storage medium for this purpose are also disclosed.