Optical Disc Format Discrimination via Central Error Signal Threshold
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Solution Overview
Problem
Conventional optical disc devices face inefficiencies in quickly identifying the format of loaded optical discs, particularly in distinguishing between R-type and ROM-type media, leading to time delays in data retrieval as the actual disc format is unknown until the lead-in area is accessed.
Innovation Solution
The method involves detecting and amplifying the central error signal during the focus-on procedure under close-loop control, using a threshold to differentiate between R-type and ROM-type media based on the peak-to-peak value of the amplified signal, with the optical pickup unit's physical characteristics determining the amplification rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the conventional calibrating procedure is used to identify disc format by accessing the lead-in area, then the disc format can be correctly recognized, but the time required for data retrieval is increased
Solution Approach 1:
The patent applies preliminary action by detecting the central error signal during the focus-on procedure before the calibrating procedure completes. This allows the disc format to be identified in advance, eliminating the time delay that would otherwise occur while waiting for the lead-in area to be accessed during calibration.
Solution Approach 2:
The patent uses the central error signal as an intermediary indicator to indirectly identify disc format. Instead of directly accessing the lead-in area to determine format, the system uses the central error signal characteristics (peak-to-peak value) as a mediator that correlates with disc type, enabling faster identification.
2Ease of operation
If the optical disc device assumes a default disc structure during calibration, then the calibration can proceed, but the actual disc format cannot be recognized immediately
Solution Approach 1:
The patent implements feedback by continuously monitoring the central error signal during the focus-on procedure and using this information to determine disc format. The feedback from the central error signal characteristics allows the system to identify the actual disc format without interrupting the calibration procedure, resolving the contradiction between maintaining calibration continuity and obtaining format information.
3Adaptability or versatility
If s-curves are used to identify disc structure, then the disc can be recognized as CD or DVD, but the distinction between R-type and ROM-type media cannot be made
Solution Approach 1:
The patent applies parameter changes by transitioning from using only s-curve waveforms (which indicate disc structure) to also measuring the peak-to-peak value of the central error signal (which indicates disc type). This additional parameter measurement enables the system to distinguish between R-type and ROM-type media while maintaining the existing disc structure identification capability.
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 rapid and accurate identification of the optical disc format, reducing the time required to recognize the disc type and enabling immediate data retrieval by distinguishing between R-type and ROM-type media, such as DVD-R and DVD-ROM, respectively.
Implementation Method 1
a light beam radiated from a light source 101 is guided and reflected by a beam splitter 107 and a mirror 109, and then penetrates a lens 111 to project onto the loaded optical disc 103. Thereafter, a reflected light beam, which sequentially penetrating the lens 111, reflected by the mirror 109, and penetrating the beam splitter 107, is finally detected by a photodetector 105
Implementation Method 2
a reflected light beam, which sequentially penetrating the lens 111, reflected by the mirror 109, and penetrating the beam splitter 107, is finally detected by a photodetector 105 and then converted into several detection signals
Data Source
AI summary
A discriminating method of ascertaining the format of the loaded optical disc for an optical disc device is disclosed. When the optical disc device operates under a close-loop control, related central error signal is amplified and measured, while the peak-to-peak value of the amplified central error signal is then compared with a threshold. The loaded optical disc will be discriminated as a R-type medium if the peak-to-peak value of the amplified central error signal is larger than the threshold. On the contrary, the loaded optical disc is identified as a ROM-type medium if the peak-to-peak value of the amplified central error signal is smaller than the threshold.