Multilayer Optical Disc Management Area for Layer Type Access
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Solution Overview
Problem
Multilayer optical discs with information layers conforming to different standards face challenges in quickly accessing and identifying the presence and type of other information layers, leading to increased access time when switching between layers.
Innovation Solution
Incorporating a management area on the highest recording density information layer to record information about the presence and type of other information layers, allowing the optical disc device to efficiently identify and access them by pre-selecting the appropriate tracking error signal method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a multilayer optical disc has information layers conforming to different optical disc standards, then the disc can store information according to multiple standards, but it takes time to access other information layers when the need arises suddenly
Solution Approach 1:
The invention applies preliminary action by recording management information about other information layers in advance on the current layer. This management information includes the presence, type, and location of other layers, allowing the optical disc device to quickly access and switch to other layers without time-consuming detection when switching is needed.
2Device complexity
If the type of one information layer is not recorded on another layer, then the disc structure remains simple, but the optical disc device must read the type of each layer every time it accesses a different layer to select a method of generating a tracking error signal
Solution Approach 1:
The invention applies preliminary action by pre-recording the type information of each information layer on every layer. This allows the optical disc device to immediately identify the layer type and select the appropriate tracking error signal generation method without performing time-consuming detection during layer transitions.
3Adaptability or versatility
If the optical disc device reads the type of each layer every time it accesses a different layer, then the device can adapt to different layer types, but access time increases due to repeated detection
Solution Approach 1:
The invention applies preliminary action by pre-recording management information including layer types on each layer. This allows the optical disc device to quickly retrieve layer type information from the pre-recorded data rather than performing time-consuming detection during layer transitions, thereby improving access speed while maintaining adaptability.
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 significantly reduces access time by enabling the optical disc device to quickly determine the type and presence of other information layers, optimizing access and recording operations based on pre-recorded information.
Implementation Method 1
a beam 3a emitted from a blue-violet semiconductor laser light source 2a, which has a wavelength of about 405 nm... is focused to a focused spot 7a on information layer L1 by an objective lens 6
Data Source
AI summary
In a multilayer optical disc having information layers conforming to a plurality of different optical disc standards, because the type of each information layer is not recorded in the other information layers, in read and write operations by a compatible optical disc device conforming to a plurality of optical disc standards, every time the information layer being accessed changes, it has been necessary to read the type of the information layer and select a method of generating a tracking error signal adapted to the type of information layer, so access has taken time. In order to solve the above problem, in the optical multilayer disc according to the present invention, having information layers conforming to a plurality of different optical disc standards, in an area in one of the information layers, information about the other information layers is recorded. The time required to access the other information layers can be reduced by using this information to select a tracking error signal generating method.