Optical Disk Radial Marks for Reflectance Data Recording
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional optical disks based on phase-change and organic dye recording systems face challenges in stabilizing the reproduction of information due to differences in reflectance between HL and LH disks, leading to inconsistent signal levels and prolonged gain adjustment times, making it difficult to reproduce data quickly and reliably across both types.
Innovation Solution
An optical disk design that includes a bar code area with radially extending marks to record information about reflectance, allowing for quick identification and adjustment of signal gain, independent of the disk type, using a phase-change material with specific Bi, Ge, and Te compositions, and an organic dye layer to enhance recording density and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional optical disks use different reflectance designs for HL and LH disk types, then the recording and reproducing can be optimized for each type, but the reproduction consistency and signal level stability deteriorate across different disk types
Solution Approach 1:
The patent changes the reflectance parameter of the bar code area to be uniform across both HL and LH disk types. By setting the bar code area reflectance to 15% for both disk types (while maintaining different user data area reflectances), the system achieves consistent signal levels for control data reproduction, eliminating the need for type-specific gain adjustments and improving reproduction consistency across different disk types.
2Measurement precision
If the gain adjustment is performed based on disk type identification, then the signal level can be optimized, but the time required for reproduction is prolonged
Solution Approach 1:
The patent performs preliminary action by pre-setting the bar code area reflectance to a standardized value (15%) that is identical for both HL and LH disk types. This preliminary standardization eliminates the need for subsequent gain adjustment based on disk type identification. The reproducing apparatus can immediately use a fixed gain value for control data reproduction, significantly reducing the time required while maintaining accurate signal levels.
3Ease of operation
If the bar code area reflectance is set uniformly for both HL and LH disks, then the control data reproduction is simplified, but the optimization for specific disk types is reduced
Solution Approach 1:
The patent applies local quality by differentiating the reflectance characteristics between different areas of the optical disk. The bar code area is assigned a uniform reflectance of 15% for both HL and LH disks to simplify control data reproduction, while the user data areas maintain their respective optimized reflectances (high reflectance for HL, low reflectance for LH). This localized differentiation allows simplified operation for control functions while preserving manufacturing precision for data storage functions.
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
Enables quick and reliable reproduction of control and user data, along with servo signals, without requiring type-specific gain adjustments, by accurately determining the reflectance relationship and optimizing signal amplification based on the recorded information in the bar code area, thus improving tracking control and data integrity.
Implementation Method 1
the phase-change recording system, which is adopted, for example, for DVD-RAM and DVD-RW... a phase-change material is used for a recording layer... pieces of information of '0' and '1' are recorded to correspond to the crystalline state (non-recorded state) and the amorphous state (recorded state) of the phase-change material respectively
Implementation Method 2
the light beam having a relatively high power is radiated so that the temperature of the irradiated portion of the recording layer is raised to a temperature which is not less than the melting point of the recording layer material... the light beam having a relatively low power is radiated so that the temperature of the irradiated portion of the recording layer is raised to a temperature which is not more than the melting point of the recording layer material and which is in the vicinity of the crystallization temperature
Implementation Method 3
the refractive index differs between areas in the crystalline state and the amorphous state formed in the recording layer... the light beam is radiated onto the crystallized portion and the amorphous portion to detect the difference in the reflected light amount between the respective portions of the optical disk so that '0' and '1', which are recorded in the recording layer, are detected
Data Source
AI summary
An optical disk includes a first area on which user information is recorded, and a second area in which a plurality of marks radially extending are arranged in a track direction in the optical disk. Information about the reflectance of the optical disk is recorded in the second area. It is intended to optimize the amplification factor of the reproduced signal on the basis of the information about the reflectance of the optical disk in the second area. Control data and user data can be reproduced quickly and highly reliably without depending on the relationship between the reflectances of a recording area and a non-recorded area of the optical disk.