Multi-Layer Optical Disc Power Ratio Optimization
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Solution Overview
Problem
Optimizing the recording conditions for multi-layer recordable optical discs is time-consuming, especially when the ratio of recording power to bias power is fixed, and the discs are exposed to varying environmental conditions, leading to deteriorated recording characteristics and prolonged optimization times.
Innovation Solution
The method involves calculating and adjusting the power ratio of bias power to maximum laser power for each recording layer independently, allowing for the determination of optimum recording conditions within a shorter period by modulating the laser power with a constant ratio, thereby optimizing the recording power to achieve a minimum error rate with fixed wavelength and waveform.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the ratio of recording power to bias power is fixed for all recording layers, then the optimization process is simplified, but the recording characteristics of one or more layers become significantly deteriorated
Solution Approach 1:
The patent divides the recording power optimization into separate processes for each recording layer. Instead of using a single fixed power ratio for all layers, the system independently determines the optimal recording power and bias power for each layer (L0, L1, etc.), allowing each layer to be optimized according to its specific characteristics while maintaining manageable complexity through systematic segmentation of the optimization process.
2Manufacturing precision
If the recording power is optimized for each recording layer independently with different power ratios, then the recording characteristics of each layer are improved, but the time required to find optimum recording conditions increases
Solution Approach 1:
The patent applies preliminary action by first determining the optimal recording power and bias power for the first recording layer (L0) before proceeding to optimize subsequent layers. The system uses the optimized parameters from L0 as a reference point and systematically adjusts parameters for L1 and other layers based on their specific characteristics. This staged preliminary optimization reduces the total search space and time required compared to independently optimizing all layers simultaneously.
3Duration of action of stationary object
If the information storage medium is preserved for a long period or in severe environmental conditions, then the medium durability is improved, but the optimum recording power changes requiring re-optimization
Solution Approach 1:
The patent implements feedback mechanisms to detect and compensate for changes in recording characteristics after long-term preservation or exposure to severe environmental conditions. The system includes processes to re-measure and re-optimize recording powers and bias powers for each layer based on actual performance feedback. This allows the system to adapt to drift in recording characteristics caused by aging, temperature variations, humidity, or other environmental factors, maintaining optimal recording conditions throughout the medium's service life.
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 the rapid determination of optimal recording conditions for multi-layer optical discs, reducing the time required to find suitable parameters and improving recording characteristics across layers, even under varying environmental conditions.
Implementation Method 1
recording marks in which the reflectivity of the dye has been changed are formed by modulating the power of a laser light
Implementation Method 2
information is recorded on a data area of a multi-layer disc having a plurality of recording layers wherein mark and space portions are formed using a laser whose output power is modulated
Data Source
Figure 1(a)~1(e)
Figure 2
Figure 3
AI summary
Single-sided dual-layer recordable disc 100 may be used. Information recording is performed by forming mark and space portions on data area DA using modulated laser power. Pp denotes the maximum laser power or peak power for forming the mark portion, and Pb denotes the bias power for forming the space portion. Power ratio Pb/Pp is calculated (ST16) for each of recording layers L0 and L1. Information is recorded (ST14-ST22) on any of the recording layers L0 and L1 based on the result of calculation. Here, the calculated power ratio Pb/Pp changes among the recording layers L0 and L1, thereby optimizing the recording condition for a multi-layer recordable optical disc within relatively short time.