Optical Pickup Power Control via Threshold Current Compensation
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Solution Overview
Problem
Conventional power control methods for optical disk drives fail to accurately control output power at different temperatures and accessing modes due to the neglect of threshold current, leading to errors in operating current computation and reduced performance and lifespan of the optical pickup head and drive.
Innovation Solution
A power control method that measures the temperature of the optical read/write module, predicts the threshold current, determines the accessing mode, measures output power, computes the required current based on base power and accessing mode, and compensates for the threshold current to drive the optical read/write module accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the conventional technique computes the operating current based on power feedback signal without considering threshold current, then the computation is simple, but the output power control precision deteriorates at different temperatures
Solution Approach 1:
The patent measures the temperature of the optical pickup head in advance and predicts the threshold current based on the temperature characteristic curve before computing the operating current. This preliminary action of obtaining temperature and predicting threshold current resolves the contradiction by preparing necessary compensation data beforehand, enabling precise power control without excessive computation complexity during operation.
Solution Approach 2:
The patent changes the computation parameters by introducing temperature as an additional parameter and using the predicted threshold current to compensate the operating current calculation. Instead of using a fixed computation method, the system dynamically adjusts the current computation based on temperature variations, thereby maintaining precision across different operating conditions without significantly increasing system complexity.
2Device complexity
If the conventional technique uses a single base power for feedback control, then the control method is simple, but the output power accuracy deteriorates for different accessing modes
Solution Approach 1:
The patent applies different base powers for different accessing modes (reading, rewriting, blocking, castle writing, multi-pulse writing) instead of using a single universal base power. Each accessing mode has its own optimized base power value stored in a table, allowing precise power control tailored to specific operational requirements while maintaining relatively simple control logic through table-based selection.
3Productivity
If the temperature and threshold current are insufficient, then the conventional computation method works adequately, but when temperature and threshold current are sufficient or precise control is required, the error becomes inevitable
Solution Approach 1:
The patent implements a feedback mechanism where the measured output power is compared with the target power, and the difference is used to adjust the operating current through compensation based on the predicted threshold current. This feedback loop ensures that even when temperature and threshold current effects are significant, the system can maintain precise power control by continuously monitoring and adjusting the operating parameters.
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 method ensures precise control of output power at different temperatures and accessing modes, enhancing the accuracy and longevity of the optical disk drive by correctly computing the operating current, thereby improving the optical pickup head's performance and the overall drive's endurance.
Implementation Method 1
measuring the temperature of the optical read/write module
Implementation Method 2
an optical read/write module (11) for accessing an optical storage medium, wherein the optical read/write module includes a light-emitting unit (111)
Data Source
AI summary
A power control method is provided for an optical disk drive. The optical disk drive has an optical read/write module for accessing an optical storage media. The power control method includes the following steps: measuring the temperature of the optical read/write module; predicting a threshold current of the optical read/write module according to the temperature; determine the accessing mode of the optical storage media; measuring the output power of the optical read/write module; computing a first current required for the optical read/write module according to the output power of the optical read/write module and a base power in the accessing mode; compensating the computed first current according to the predicted threshold current; and driving the optical read/write module according to the first current.