Optical Recording Pulse Power Segmentation for Edge Precision
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Solution Overview
Problem
Conventional optical information recording methods face challenges in achieving precise recording with simple circuit structures due to variations in mark edge resolution and thermal characteristics of optical disks, leading to increased manufacturing costs and complex circuit requirements.
Innovation Solution
The method involves correcting the edge position of recording pulses and setting different power levels for the front and rear portions of the recording pulse or pulse train based on the record code length, allowing for precise information recording using a simple circuit structure without the need for high-resolution delay lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional recording methods are used to achieve precise recording, then manufacturing precision is improved, but device complexity increases due to high-resolution delay lines and complex circuit structures
Solution Approach 1:
The recording pulse is divided into multiple segments (front end pulse, middle pulse, rear end pulse) with different power levels. This segmentation allows independent optimization of each pulse segment to compensate for thermal effects at different mark positions, achieving precise recording without complex delay lines.
Solution Approach 2:
Different power levels are assigned to different portions of the recording pulse train based on their specific thermal requirements. The front end pulse uses higher power to overcome heat conduction from previous marks, the middle pulse uses moderate power, and the rear end pulse uses lower power to prevent overheating, creating local quality variations that improve overall recording precision.
2Manufacturing precision
If high-resolution delay lines are used to correct mark edge positions, then manufacturing precision is improved, but manufacturing cost increases
Solution Approach 1:
Instead of using high-resolution delay lines to adjust timing parameters, the invention changes the power level parameter of the recording pulse. By varying the power levels of different pulse segments, the effective thermal impact at different mark edges is controlled, achieving position accuracy through parameter optimization rather than precise timing adjustment.
3Device complexity
If uniform power levels are used throughout the recording pulse train, then device complexity is reduced, but manufacturing precision deteriorates due to thermal interference between marks
Solution Approach 1:
The recording pulse train is designed with non-uniform power distribution where the front end pulse has higher power than the middle and rear pulses. This local quality variation compensates for heat conduction effects from previous marks, ensuring consistent mark shapes and edges throughout the recording process while maintaining relatively simple circuit implementation.
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 improves the accuracy of recorded information while reducing manufacturing costs by enabling precise edge position correction and power level adjustments, facilitating efficient data recording with a simplified circuit design.
Implementation Method 1
A laser beam having a power higher than a reproducing power (this power level is called the recording power and is denoted by Pw) is focused by an optical head and applied to a recording film of the optical disk so that a temperature of the recording film is raised above its melting point. Then, the melted portion is cooled rapidly when the laser beam passes so that a mark is formed having an amorphous state.
Implementation Method 2
when a laser beam having a power such that it can raise the temperature of the recording film above a crystallizing temperature and below the melting point (this power level is called an erasing power and is denoted by Pe) is focused and applied, the applied portion of the recording film becomes crystalline.
Implementation Method 3
A laser beam having a power higher than a reproducing power (this power level is called the recording power and is denoted by Pw) is focused by an optical head and applied to a recording film of the optical disk
Data Source
AI summary
A recording and reproducing method is provided in which information can be recorded and reproduced correctly using a simple circuit structure, even with a high transfer rate, and a test record can be performed efficiently in a short time. A laser driving circuit 6 makes power levels of a front end pulse and a rear end pulse different from a power level of a middle pulse, and a record signal edge correction circuit 5 corrects an edge position of a recording pulse.