Optical Disc Drive Track Skipping Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical disc drives face challenges in accurately detecting 'track skipping' on both write-once and rewritable discs, leading to potential data loss or corruption due to incorrect detection based on tracking error signals, especially with narrow track pitches like BDs, where tracking errors can mimic track skipping.
Innovation Solution
An optical disc drive with disc recognizing means to differentiate between write-once and rewritable discs, using distinct conditions for track skipping detection, such as discontinuity in physical addresses for write-once discs and tracking error signals for rewritable discs, to prevent unnecessary data stoppage and ensure accurate detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If track skipping detection is performed using tracking error signals on write-once discs, then track skipping can be detected quickly, but false detection occurs due to tracking errors mimicking track skipping on narrow track pitch discs
Solution Approach 1:
The patent changes the detection parameter from tracking error signal to physical address continuity for write-once discs. By monitoring whether physical addresses are continuous during writing, the system can accurately detect track skipping without the false positives that occur when using tracking error signals on narrow track pitch discs like BDs.
2Measurement precision
If track skipping detection threshold is set low for accurate detection, then false stoppage occurs due to normal tracking errors, but if threshold is set high, then actual track skipping may be missed
Solution Approach 1:
The patent introduces physical address information as an intermediary indicator to detect track skipping. Instead of directly using tracking error signals that cause false positives, the system monitors physical address continuity as a more reliable intermediary metric that accurately reflects actual track skipping events without triggering false stoppages.
3Device complexity
If a single track skipping detection method is used for both write-once and rewritable discs, then device complexity is reduced, but detection accuracy deteriorates due to different optimal detection conditions for each disc type
Solution Approach 1:
The patent applies different detection methods tailored to each disc type: using physical address continuity monitoring for write-once discs and tracking error signal analysis for rewritable discs. This localized optimization ensures that each disc type is monitored using the most appropriate method, maximizing detection accuracy for both types without requiring a single complex unified system.
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 enhances the detection of track skipping on both types of discs, reducing data loss and maintaining data integrity by tailoring detection methods to the specific disc type, thus preventing erroneous data writing and ensuring readability.
Implementation Method 1
Data stored on an optical disc can be read out from the disc by irradiating the rotating disc with a relatively weak light beam with a constant intensity, and detecting the light that has been modulated by, and reflected from, the optical disc.
Implementation Method 2
In writing data on such a rewritable or write-once optical disc, data is written there by irradiating the optical disc with a light beam, of which the optical power has been changed according to the data to be written, and locally changing the properties of the recording material film.
Data Source
AI summary
An optical disc drive according to the present invention can write data on both a write-once disc and a rewritable disc. The drive includes: a disc recognizing section 110 for recognizing the type of a given optical disc as a write-once disc or a rewritable disc; and track skipping detection signal generating section, which outputs track skipping detection signal when a first condition on tracking error is satisfied if the given optical disc, on which data is being written, has turned out to be a write-once disc. On the other hand, if the given optical disc has turned out to be a rewritable disc, the track skipping detection signal generating section outputs track skipping detection signal when a second condition on tracking error, which is different from the first condition, is satisfied. A control section stops writing the data in response to the track skipping detection signal while the data is being written.