Optical Disk Recording Method Using Multi-Pulse Chains
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Solution Overview
Problem
Next-generation optical disks face challenges in accurately recording small mark/space lengths due to thermal interference and reduced resolving power, requiring improved correction techniques for mark edge shift across various recording media and recording modes.
Innovation Solution
An optical disk recording method and device that adjusts the position and width of energy beam pulses based on mark and space lengths using multi-pulse chains and mono pulses, with reference tables for optimal pulse timing control, allowing for accurate recording on different recording media without changing the fundamental waveform.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the distance between positions irradiated with two recording pulses is reduced to increase recording density, then recording capacity increases, but mark geometrical distortion and mark edge shift occur due to overlapping light intensity distributions
Solution Approach 1:
The patent applies periodic pulsed irradiation with multiple power levels (first power level for mark formation, second power level lower than first, third power level lower than second) in a repeating sequence. This periodic action with varying intensity levels allows precise control of mark edge positions while maintaining high recording density by preventing thermal accumulation that causes distortion.
Solution Approach 2:
The patent changes the power level parameter dynamically during recording by switching between first, second, and third power levels at different time intervals. This parameter change enables precise control of the light intensity distribution over time, allowing marks to be formed accurately even when pulse distance is reduced for high-density recording.
2Quantity of substance
If the mark or space length is reduced to increase data density, then recording capacity increases, but mark edge shift occurs because the mark or space cannot be discriminated sufficiently on the basis of playback light spot
Solution Approach 1:
The patent uses periodic pulsed irradiation with at least two different power levels where pulses are applied at specific intervals. This periodic action creates distinct thermal zones that correspond to mark and space regions, enabling sufficient discrimination even when the physical length of marks and spaces is reduced for high data density.
Solution Approach 2:
The patent applies different power levels (first power level for mark portions, second and third power levels for space portions) to different local regions of the recording medium. This local quality differentiation ensures that even short marks and spaces can be clearly distinguished during playback by creating distinct optical property variations in each region.
3Manufacturing precision
If a multi-pulse chain recording strategy is used to correct mark edge shift, then mark edge position accuracy improves, but the recording strategy must be changed for different recording films reducing adaptability
Solution Approach 1:
The patent provides a universal recording method that works with different recording films (phase change films, organic coloring films, dye films) by using a standardized multi-power-level pulsed irradiation approach. The method achieves mark edge correction across various film types without requiring film-specific strategy changes, making the system highly adaptable.
Solution Approach 2:
The patent adjusts power level parameters (first, second, and third power levels) and pulse timing parameters based on the specific recording film being used. This parameter adaptation allows the same fundamental multi-power-level approach to be universally applied to different film types while optimizing performance for each specific medium.
4Reliability
If the pulse width is increased to improve mark formation, then recording reliability improves, but thermal interference increases causing mark edge shift
Solution Approach 1:
The patent uses periodic pulsed irradiation with multiple power levels where the beam is turned on and off in a repeating sequence. This periodic action with alternating high and low power levels ensures sufficient energy delivery for reliable mark formation while preventing thermal accumulation that would cause interference and edge shift.
Solution Approach 2:
The patent segments the continuous irradiation process into discrete pulses with at least two different power levels. This segmentation allows the recording process to deliver necessary energy in controlled bursts for reliable marking while creating cooling intervals that prevent thermal interference between adjacent marks.
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
Enables accurate recording of small mark/space lengths on various media, compensating for mark edge shifts caused by thermal interference and resolving power issues, ensuring compatibility with both high-speed and low-speed recording modes.
Implementation Method 1
irradiating the recording film with a multi-pulse chain of an energy beam... capable of being changed to an optically different state by irradiation with an energy beam
Implementation Method 2
mark edge shift caused by thermal interference at the time of recording
Data Source
AI summary
An optical disk recording method includes the steps of: providing a multi-pulse chain from a recording wave; independently changing the pulse rise timing and pulse fall timing (pulse width) of the first pulse in the multi-pulse chain in accordance with a preceding space length and a recording mark length; changing the pulse rise timing and pulse fall timing (pulse width) in accordance with a following space length and the recording mark length in a predetermined timing or in independence; and in relation to the smallest mark recorded by irradiation with mono pulse, changing the rise timing in accordance with the preceding space length and the recording mark length and the fall timing (pulse width) in accordance with the following space length and recording mark length, compensating various optical disks different in recording material without change of the fundamental waveform.