Phase-change optical recording medium tracking signal initialization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional optical storage media and recording methods fail to provide sufficient overwrite characteristics, particularly at high linear-velocity recording speeds due to adverse jitter issues in initial overwriting and subsequent overwriting processes.
Innovation Solution
A phase-change optical storage medium and method where the recording layer is initialized in a crystalline state with specific reflectivity characteristics, using a laser beam to modulate the erasing power and recording pulses to achieve optimal reflectivity changes, ensuring excellent overwrite characteristics at high linear-velocity recording speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional initialization methods are used, then recording density and repeated recording characteristics are improved, but overwrite characteristics at high linear velocity deteriorate
Solution Approach 1:
The invention changes the parameter of tracking signal amplitude by controlling initialization laser power to achieve a specific range (0.05 to 0.20 of saturation value), which simultaneously improves overwrite characteristics at high linear velocity while maintaining recording density and repeated recording characteristics
Solution Approach 2:
The invention applies preliminary initialization treatment with controlled laser power before recording to set the tracking signal amplitude in the optimal range, ensuring excellent overwrite characteristics are established in advance for high linear velocity operation
2Ease of operation
If conventional erasing power settings are used, then basic erasing function is achieved, but jitter characteristics in initial overwriting deteriorate
Solution Approach 1:
The invention uses feedback by measuring the tracking signal amplitude and adjusting the initialization laser power accordingly to maintain the amplitude within the optimal range, which improves jitter characteristics in initial overwriting while maintaining erasing functionality
Solution Approach 2:
The invention makes the initialization process dynamic by adjusting laser power based on the measured tracking signal characteristics, allowing optimal performance across different recording conditions and speeds
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 solution provides stable and excellent overwrite characteristics, maintaining low jitter levels even at high recording speeds, such as DVD 4× speed (14 m/s), ensuring reliable data recording and rewriting.
Implementation Method 1
recording pulses are applied (irradiated) onto a recording layer with a laser beam having a recording power, to melt and rapidly cool down the recording layer, thus forming amorphous recorded marks thereon
Implementation Method 2
melt and rapidly cool down the recording layer
Implementation Method 3
a laser beam having a power (erasing power) smaller than the recording power is irradiated onto the recording layer to raise the temperature thereof to a temperature in the range from the crystallization temperature to the melting point to change the recording layer from the amorphous phase to the crystalline phase
Implementation Method 4
raise the temperature thereof to a temperature in the range from the crystallization temperature to the melting point
Implementation Method 5
Reflectivity of the recorded marks lower than that of the crystalline-phase recording layer allows optical reading of the marks as recorded data
Data Source
AI summary
A phase-change optical storage medium has a substrate and a recording layer having a plurality of tracks for storing information. A material of which the recording layer is made has been initialized in a crystalline state in which an amplitude of a tracking-detection signal is smaller than a saturation value of the amplitude, the tracking-detection signal being obtained by receiving a reflected beam from the recording layer when the recording layer is irradiated with a laser beam in an off-track state while the optical storage medium is being rotated.