Optical Disc BCA Layer Identification via Segmented Pre-Format
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Solution Overview
Problem
The existing information recording media with separate servo and data layers face challenges in accurately determining the number of data layers during recording and reproduction due to signal leakage and interference, especially when using Burst Cutting Area (BCA) information, which degrades the reproduction signals and makes it difficult to accurately focus on the correct data layer.
Innovation Solution
The proposed solution involves an information recording medium with pre-format areas on each data layer, where identification information is recorded as a sequence of marks, and BCA information is allocated in specific segments to avoid overlap and signal interference, using a correspondence table to manage the layer and segment numbers, allowing accurate determination of the current data layer being read.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If BCA information is recorded on data layers in a guide layer type optical disk, then layer identification is enabled, but signal leakage between adjacent layers occurs and BCA reproduction signals are degraded
Solution Approach 1:
The pre-format area is divided into multiple segments along the radial direction, and BCA information is recorded in specific segments rather than continuously. This segmentation isolates the BCA information in discrete regions, preventing signal leakage to adjacent layers while maintaining layer identification capability.
Solution Approach 2:
Different regions of the pre-format area are assigned different functions: some segments store BCA information for layer identification, while other segments are left empty or contain different data. This local differentiation ensures that BCA information is recorded only where needed, minimizing interference with adjacent layers.
2Quantity of substance
If the number of data layers is increased to realize large capacity, then recording capacity is improved, but the number of shape forming steps increases and productivity decreases
Solution Approach 1:
Multiple data layers share a common pre-format area structure, allowing the same shape-forming process to be applied to all layers. This merging of the pre-format area across layers eliminates the need for separate shape-forming steps for each layer, maintaining high productivity even with increased data layer capacity.
3Measurement precision
If focus servo setting areas with different reflectance ratios are provided along the radius, then focus positioning accuracy is improved, but there is no means to determine which data layer is actually focused after the setting operation
Solution Approach 1:
The pre-format area with recorded BCA information acts as an intermediary between the focus servo setting areas and the data layers. After focus positioning is achieved through reflectance ratio differentiation, the BCA information in the pre-format area provides the necessary identification of which data layer is currently focused, bridging the gap between positioning and identification.
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 effectively reduces signal cross-talk and enhances the accuracy of BCA reproduction signals, enabling reliable access to the correct data layer and improving the overall recording and reproduction process by minimizing interference and ensuring precise layer identification.
Implementation Method 1
there is a technique of providing focus servo setting areas of different reflectance ratios along the radius of a disk
Data Source
AI summary
According to one embodiment, in an information recording medium including a plurality of data layers, at least one pre-format area is provided on each of the data layers and is circumferentially divided into a plurality of segments. Management information including data layer identification information for identifying the data layers is recorded in at least one of the segments in each of the data layers, using the marks include BCA marks extending radially uniformly. On adjacent ones of the data layers, the BCA marks associated with the management information are recorded in differently positioned segments which are not opposed to each other.