Optical Disc Label Surface Image Drawing via Prepits

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Solution Overview

Problem

Existing optical disc technologies face challenges in accurately drawing images on the label surface without compromising the recording process, often requiring additional equipment like printers and resulting in cumbersome processes and potential errors due to the lack of recognition mechanisms for the optical disc recording apparatus.

Innovation Solution

The optical disc features a substrate with prepits on the surface, where the image recording layer is formed, with specific depth and width ranges to enhance signal accuracy and allow the optical disc recording apparatus to recognize and draw images correctly, ensuring proper signal detection and image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If a printer is used to print titles on a label sheet and the label sheet is attached to the optical disc, then visible information can be provided on the optical disc, but additional equipment is required and the process becomes cumbersome

Engineering Contradiction:
Improvevisible informationVSAvoidadditional equipment
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent combines the information recording layer and the label surface into a single integrated structure. The label surface is formed on the same substrate as the information recording layer, eliminating the need for separate label sheets and printers. This merging of functions allows visible information to be directly provided on the optical disc without requiring additional printing equipment or manual label attachment processes.

Inventive Principle:
Principle #5Merging (Combining)

2Loss of information

If an optical disc recording apparatus is used to draw images on the label surface, then visible images can be formed, but the apparatus lacks accuracy and stability without tracking

Engineering Contradiction:
Improvevisible imageVSAvoidimage drawing accuracy
Core Design Contradiction:
Loss of informationVSManufacturing precision

Solution Approach 1:

The patent introduces guide grooves as an intermediary structure between the information recording layer and the label surface. These guide grooves serve as tracking paths that enable the optical disc recording apparatus to accurately position and draw images on the label surface. The guide grooves act as a mediator that provides the necessary tracking reference, thereby improving image drawing accuracy and stability without requiring complex additional positioning systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Quantity of substance

If the track pitch of the guide groove is narrowed to increase recording density, then higher density recording can be performed, but the disc becomes more sensitive to manufacturing errors and handling

Engineering Contradiction:
Improverecording densityVSAvoiddisc sensitivity
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent applies different structural characteristics to different regions of the optical disc. The guide grooves are designed with specific pitch and depth parameters optimized for tracking and positioning, while the information recording layer maintains high-density recording capabilities. This local differentiation allows the guide groove region to provide stable tracking with adequate pitch, while the data recording region achieves high density, thereby resolving the conflict between recording density and manufacturing reliability.

Inventive Principle:
Principle #3Local quality

4Measurement precision

If prepits are formed on the substrate surface to enable recognition and image drawing, then the optical disc recording apparatus can recognize the disc, but the depth and width of prepits must be precisely controlled to avoid signal detection errors

Engineering Contradiction:
Improvesignal detection accuracyVSAvoidprepit dimension control
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent specifies optimal parameter ranges for prepit depth (100-400 nm) and width to achieve the desired balance between signal detection accuracy and manufacturing feasibility. By defining these parameter ranges, the invention transforms the precision control problem into a manufacturable specification, allowing standard manufacturing processes to produce prepits within the optimal range that provide sufficient signal contrast for accurate recognition while accommodating normal manufacturing variations.

Inventive Principle:
Principle #35Parameter changes

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 configuration improves the accuracy of signal detection and image drawing by adjusting the prepit dimensions, allowing for higher contrast and visibility of images, reducing errors, and enabling the optical disc recording apparatus to recognize the disc for precise image formation.

Implementation Method 1

an image recording layer onto which a drawing of a visible image can be performed by irradiation of laser light

Methodology Applied
Scientific EffectLaser light irradiation: Laser

Implementation Method 2

An irradiated part of the information recording layer absorbs the light and its temperature is locally increased

Methodology Applied
Scientific EffectOptical absorption: Absorption (EM radiation)

Implementation Method 3

a light reflective layer formed of metal such as gold

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 4

prebits provided on a surface of the substrate on which the image recording layer is formed, wherein a signal for recognition of the optical disc or information related to a drawing on the label surface is recorded on the prepits

Methodology Applied
Scientific EffectOptical modulation:

Data Source

PatentEP1930893B1Optical disc and method for manufacturing such optical disc
Publication Date: 2011.11.02 FUJIFILM CORP
  • EP1930893B1 patent drawingFigure 1A~1B
  • EP1930893B1 patent drawingFigure 2A~2B
  • EP1930893B1 patent drawingFigure 2C

AI summary

The invention provides an optical disc capable of recording and reproducing information using laser light. Specifically, the invention provides an optical disc on which a drawing of a visible image can be also performed using laser light, a stamper suitable for manufacturing the optical disc, a method for manufacturing the optical disc, a signal processing method that can be used in the optical disc, a signal processing apparatus, an image drawing method, an optical disc recording apparatus, and an optical recording medium.