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-setting laser power and tracking error signal methods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a multilayer optical disc has information layers conforming to different optical disc standards, then the disc can accommodate multiple standards and increase user convenience, but it takes time to access other information layers when the need to reproduce or record information on another layer suddenly arises

Engineering Contradiction:

Improvecompatibility with multiple optical disc standardsVSAvoidaccess time when switching between information layers

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent 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.

Inventive Principle:

Principle #10Preliminary action

2Device complexity

If the type of one information layer is not recorded on another layer, then the disc structure remains simple, but every time the device accesses a different information layer, it must read the type of the layer to select a method of generating a tracking error signal adapted to the type

Engineering Contradiction:

Improvedisc structure complexityVSAvoidaccess time when reading layer type information

Core Design Contradiction:

Device complexityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-recording management information about other information layers on the current layer. This management information includes the type of each layer, allowing the optical disc device to quickly identify and select the appropriate tracking error signal generation method without time-consuming detection when switching layers.

Inventive Principle:

Principle #10Preliminary action

3Loss of time

If information indicating the types of other information layers is recorded in a management area on the highest recording density layer, then access time is shortened by enabling quick identification of other layers, but the disc requires an additional management area and information recording capability

Engineering Contradiction:

Improveaccess time when switching between information layersVSAvoiddisc structure with management area

Core Design Contradiction:

Loss of timeVSDevice complexity

Solution Approach 1:

The patent applies universality by using the highest recording density layer's management area to store information about other layers. This approach leverages the existing management area structure of the highest density layer for an additional function - storing cross-layer management information - without requiring separate management areas on each layer.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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.

Implementation Method 1

an objective lens with higher numerical apertures, and by reducing the size of the focused light spot on the focal plane

Methodology Applied

Scientific EffectOptical focusing: Focusing

Implementation Method 2

by using laser beams having shorter wavelengths as light sources for recording and reproducing, by using objective lenses with higher numerical apertures, and by reducing the size of the focused light spot on the focal plane

Methodology Applied

Scientific EffectDiffraction limit: Diffraction

Data Source

PatentUS8213290B2Optical disc and optical disc device

Publication Date: 2012.07.03 MITSUBISHI ELECTRIC CORP

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.