Multilayer Optical Disk Recording Using Simultaneous N-Laser Beam Focusing

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Solution Overview

Problem

Current optical disk recording and reproducing technologies face limitations in achieving high-speed operations due to the complexity of managing multiple recording layers and the increased processing time required for higher storage capacities, especially with the use of blue laser technology.

Innovation Solution

A multilayer optical disk recording and reproducing apparatus that utilizes multiple laser beams of the same wavelength to simultaneously focus on alternating groups of recording layers, allowing for simultaneous recording and reproducing operations across multiple layers, thereby simplifying control and increasing speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple laser beams are simultaneously emitted from different light sources and focused onto a multilayer optical disk, then the recording speed increases, but the device complexity increases

Engineering Contradiction:
Improverecording speedVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent combines multiple laser beams of the same wavelength emitted from a single light source and focuses them simultaneously onto different recording layers of a multilayer optical disk using one objective lens. This merging approach increases recording speed by processing multiple layers in parallel while avoiding the complexity of using multiple separate light sources and objective lenses.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent transitions from processing a single recording layer to processing multiple recording layers simultaneously in the thickness direction (Z-axis). By emitting multiple laser beams at different angles and focusing them onto alternating layers, the system achieves high-speed recording without increasing radial or angular complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Quantity of substance

If the storage capacity of the optical disk is increased, then the recording capacity increases, but the processing time increases

Engineering Contradiction:
Improvestorage capacityVSAvoidprocessing time
Core Design Contradiction:
Quantity of substanceVSLoss of time

Solution Approach 1:

The patent implements continuous parallel processing of multiple recording layers simultaneously. By maintaining continuous laser beam emission onto different layers in parallel, the system eliminates idle processing time between layer operations, thereby reducing total processing time while increasing storage capacity through multilayer utilization.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent prepares and emits multiple laser beams in advance, each targeted at different recording layers, enabling simultaneous data writing across multiple layers before the process begins. This preliminary arrangement of beams allows the system to process data continuously across all layers without sequential delays.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If multiple laser beams are focused on alternating recording layers, then the control complexity is simplified, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvecontrol complexityVSAvoidmanufacturing precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent applies different focal positions and angles to each laser beam according to the specific requirements of different recording layers. By tailoring the local parameters (focus position, angle) of each beam to match the layer-specific requirements, the system achieves precise control while simplifying the overall management of multiple beams through standardized local adjustments.

Inventive Principle:
Principle #3Local quality

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 enables stable high-speed recording and reproducing operations, reducing the time required for data transfer and management of multiple layers, achieving speeds up to twelvefold compared to conventional systems.

Implementation Method 1

an optical pickup that emits N (N represents an integer of two or more) laser beams of the same wavelength

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 2

to focus the N laser beams on a first recording layer group

Methodology Applied
Scientific EffectFocusing: Focusing

Data Source

PatentEP2136367B1Multilayer optical disk recording apparatus and multilayer optical disk reproducing apparatus
Publication Date: 2011.06.08 HITACHI LTD
  • EP2136367B1 patent drawingFigure 1
  • EP2136367B1 patent drawingFigure 2~4
  • EP2136367B1 patent drawingFigure 5

AI summary

A multilayer optical disk apparatus (14) comprises an optical pickup (4) that emits N (N represents an integer of two or more) laser beams of the same wavelength. The optical pickup (4) emits the N laser beams at the same time, focuses the N laser beams on a first recording layer group alternately configured by N recording layers of the multilayer optical disk (1) and performs a recording operation on the N recording layers at the same time. When changing the recording layers the optical pickup (4) focuses the N laser beams on a second recording layer group configured by recording layers adjacent to the respective recording layers configuring the first recording layer group and performs a recording operation on the N recording layers at the same time.