Optical Disc Recording Condition Classification for High-Density Storage
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Solution Overview
Problem
As recording density increases, inter-symbol interference and signal-to-noise ratio (SNR) deterioration become significant issues, making it difficult to correctly detect the leading or trailing edges of small recording marks and decode information accurately, especially with high-order PRML systems requiring precise adjustment of recording conditions to minimize error rates in high-density recording.
Innovation Solution
The solution involves an information recording medium and apparatus that classify recording conditions based on the length of recording marks and adjacent spaces, using a combination of lengths to adjust recording parameters, such as the position of leading or trailing edges, to optimize recording marks and spaces, even when marks are extremely small, thereby reducing error rates and ensuring stable high-density recording.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If recording density is increased, then information storage capacity is improved, but inter-symbol interference and SNR deterioration occur making it difficult to correctly detect recording mark edges
Solution Approach 1:
The patent applies parameter changes by adjusting recording pulse conditions (power levels, pulse widths) based on the length of recording marks and adjacent spaces. Different recording parameters are selected according to the specific pattern of recording mark lengths and space lengths to optimize detection precision while maintaining high storage capacity
Solution Approach 2:
The patent implements local quality by classifying recording conditions into multiple groups based on combinations of recording mark length and adjacent space length. Each group receives customized recording parameters tailored to its specific characteristics, allowing precise control of thermal interference effects in different local regions of the recording medium
2Quantity of substance
If recording mark size is reduced to increase density, then storage capacity is improved, but thermal interference from adjacent marks increases causing detection errors
Solution Approach 1:
The patent applies preliminary anti-action by pre-classifying recording conditions into multiple groups based on recording mark length and adjacent space length before recording. This allows the system to select appropriate recording parameters in advance that compensate for anticipated thermal interference effects from adjacent marks, preventing detection errors before they occur
Solution Approach 2:
The patent changes recording parameters (power, pulse width) based on the classified recording conditions to counteract thermal interference. By adjusting these parameters according to the specific pattern of adjacent marks and spaces, the system minimizes thermal effects while maintaining high storage density
3Measurement precision
If high-order PRML systems are used to improve detection accuracy, then measurement precision is improved, but complexity of recording condition adjustment increases
Solution Approach 1:
The patent applies segmentation by dividing recording conditions into multiple classified groups based on recording mark length and adjacent space length. This segmentation simplifies the adjustment process by organizing the complex parameter space into manageable categories, each with optimized recording parameters for high-order PRML detection
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 allows for precise adjustment of recording conditions to reduce error rates in high-density recording, enabling more stable and accurate reproduction of information by considering the thermal interference effects of adjacent marks, thus improving the reliability of high-order PRML systems.
Implementation Method 1
A recording mark of each length is formed by a recording pulse sequence including at least a first pulse (also referred to as a 'leading pulse'). The recording mark further includes a last pulse and at least one middle pulse located between the first pulse and the last pulse, depending on the length of the recording mark.
Implementation Method 2
the cooling power Pc203 may be set to a different value from the bottom power Pb202 in order to adjust the heat amount at an end of a recording mark
Data Source
AI summary
An information recording medium according to the present invention includes a track on which a data sequence including a plurality of recording marks and a plurality of spaces provided between the plurality of recording marks is recordable; and a recording condition recording area in which a recording condition for recording the data sequence on the track is recordable. Where a recording mark which is included in the data sequence and is to be formed on the track based on the recording condition is a first recording mark, when a length of the first recording mark is longer than a prescribed length, the recording condition is classified using a combination of the length of the first recording mark and a length of a first space located adjacently previous or subsequent to the first recording mark, and when the length of the first recording mark is equal to or shorter than the prescribed length, the recording condition is classified using a combination of the length of the first recording mark, the length of the first space, and a length of a second space not located adjacent to the first space and located adjacent to the first recoding mark.