Multi-layer Optical Disc Radial Spare Area Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing rewritable information recording media with multiple recording layers lack effective defect management, leading to decreased access speed and reliability due to independent defect sector management in each layer, and arbitrary spare area assignment which can cause radial position deviations during laser light transition between layers.
Innovation Solution
A multi-layered information recording medium with contiguous spare areas in each recording layer, where spare areas are positioned at the same radial position and used to replace defect regions, and OPC regions are provided in each layer for independent laser power calibration, allowing for efficient defect management and improved access characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If independent defect sector management is implemented in each recording layer, then defect management coverage is improved, but access speed decreases due to radial position deviations during laser light transition between layers
Solution Approach 1:
The patent merges defect management functions across multiple recording layers by positioning spare areas at the same radial position in each layer. This allows the laser beam to maintain constant radial position while transitioning between layers, eliminating access speed degradation and enabling unified defect management coverage across all layers.
Solution Approach 2:
The patent creates equipotential conditions for laser access by aligning spare areas across different recording layers at identical radial positions. This ensures that the laser beam operates under equivalent radial position conditions when accessing spare areas in any layer, preventing access speed penalties and enabling seamless defect replacement operations.
2Adaptability or versatility
If arbitrary spare area assignment is implemented in each recording layer, then defect replacement capability is improved, but access characteristics deteriorate due to radial position deviations during laser light transition
Solution Approach 1:
The patent combines spare area positioning strategies across multiple recording layers by assigning all spare areas to the same radial position. This unified positioning approach maintains consistent access characteristics while preserving full defect replacement capability across all layers, as the laser beam does not experience radial position deviations during layer transitions.
Solution Approach 2:
The patent applies local quality optimization by specifically positioning spare areas (rather than all data areas) at identical radial positions across layers. This selective positioning maintains optimal access characteristics for defect replacement operations while allowing other areas to be positioned according to their specific functional requirements.
3Quantity of substance
If multiple recording layers are provided to increase storage capacity, then storage capacity is improved, but defect management complexity increases leading to decreased reliability
Solution Approach 1:
The patent merges defect management operations across multiple recording layers by using a unified spare area positioning strategy. All spare areas are positioned at the same radial position regardless of which layer they reside in, allowing the defect management system to operate with consistent parameters across all layers and reducing overall system complexity despite increased storage capacity.
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 solution enhances data reliability and access speed by enabling efficient spare area utilization and independent laser power calibration across multiple recording layers, ensuring continuous accessibility and increased storage capacity.
Implementation Method 1
The thickness and composition of the first recording layer 34 are calibrated such that the first recording layer 34 reflects a half of the incoming laser light 38 and transmits the other half of the incoming laser light 38
Implementation Method 2
The thickness and composition of the second recording layer 33 are calibrated such that the second recording layer 33 reflects all of the incoming laser light 38
Implementation Method 3
An objective lens 37 forgathering the laser light 38 is moved toward or away from the optical disc 30 such that the convergence point (beam spot) 36 of the laser light 38 is placed on the first recording layer 34 or the second recording layer 33
Data Source
AI summary
A multi-layered information recording medium including a plurality of recording layers, the multi-layered information recording medium comprising: a user data area for recording user data; and a plurality of spare areas including at least one replacement region, wherein when the user data area includes at least one defect region, the at least one replacement region may be used in place of the at least one defect region, wherein a first spare area of the plurality of spare areas is positioned so as to be contiguous to a first user data area of a first recording layer, a second spare area of the plurality of spare areas is positioned so as to be contiguous to a second user data area of a second recording layer, and the first spare area and the second spare area are positioned approximately at the same radial position on the multi-layered information recording medium.