Dynamic information storage or retrieval – With servo positioning of transducer assembly over track... – Optical servo system
Reexamination Certificate
2001-08-30
2004-01-27
Tokar, Michael (Department: 2819)
Dynamic information storage or retrieval
With servo positioning of transducer assembly over track...
Optical servo system
C369S044120, C369S047220, C369S053130, C369S053130, C369S053350, C369S047360, C331SDIG002, C331S00100A, C331S016000, C331S034000
Reexamination Certificate
active
06683830
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical recording medium, and more particularly, to an apparatus and method for detecting wobble defects using a wobble signal detected from the optical recording medium having a wobble pattern.
2. Description of the Related Art
Several types of optical disks such as a Digital Versatile Disk-Random Access Memory (DVD-RAM), a DVD-Recordable (DVD-R), a DVD-Rewritable (DVDRW), and a DVD+RW, have been developed to date. A wobble pattern is present at a boundary region of a land and a groove in an optical recording medium. Thus, if numerous errors occur in the wobble pattern, there is a high probability that errors occur in data regions on lands and grooves.
Furthermore, a wobble signal corresponding to the wobble pattern may be used to detect recording position information on an optical disk. Also, the wobble signal may be used as a reference clock for detecting a record/playback position or as a reference signal for generating the reference clock. Thus, it is important to detect the presence of the wobble signal corresponding to a wobble pattern on the optical recording medium for the use of the optical recording medium.
SUMMARY OF THE INVENTION
Various objects and advantages of the invention will be set forth in part in the description that follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
To solve the above problems, it is an object of the present invention to provide an apparatus and method for detecting a defect in a wobble pattern in an the optical recording medium using a wobble signal detected in an optical recording medium, in which verification is performed on a defective region if a defect exists in the wobble pattern when recording data in the optical recording medium.
Accordingly, to achieve the above and other objects, the present invention provides an apparatus for detecting a defect in a wobble pattern on an optical medium, the apparatus including: a phase-locked loop (PLL) generating phase-locked looped wobble signals and wobble clock signals in response to wobble signals from the wobble pattern; a window signal generator generating wobble window signals indicative of a wobble window period which comprises a window width condition based on the phase-locked looped wobble signals; a wobble lock/unlock detector detecting whether the wobble signals exist during the wobble window period and generating wobble lock/unlock signals setting one of a wobble unlock state when the wobble signals do not exist and satisfy a preset wobble unlock condition and a wobble lock state when the wobble signals do exist and satisfy a preset wobble lock condition; and a wobble defect detector counting the wobble window signals in response to the wobble lock/unlock signals indicating that the wobble signals do not exist during the wobble window period, detecting a wobble defect in response to the counted wobble window signals satisfying a defect decision condition, and outputting a defect detection signal indicative thereof.
The window width condition comprises the wobble window period during which a number of wobble clock signals are generated from an edge of the phase-locked looped wobble signals corresponding to a state in which the wobble signals are active. The wobble lock condition corresponds to a number at which the wobble signals are successively detected during the wobble window period. The wobble unlock condition corresponds to a number at which the wobble signals are not successively detected during the wobble window period. The predetermined defect decision condition corresponds to a number at which the wobble signals are not successively detected during a wobble window period in the wobble unlocked state.
The present invention also provides an apparatus receiving wobble signals indicative of a wobble pattern formed on an optical medium, the apparatus including: a wobble lock/unlock detector detecting whether the wobble signals exist during a wobble window period and generating wobble lock/unlock signals indicative thereof; and a wobble defect detector counting the wobble window signals in response to the wobble lock/unlock signals indicating that the wobble signals do not exist during the wobble window period, detecting a wobble defect in response to the counted wobble window signals satisfying a defect decision condition, and outputting a defect detection signal indicative thereof.
The present invention also provides a method of detecting a defect in a wobble pattern on an optical medium, the method including: generating phase-locked looped wobble signals and wobble clock signals in response to wobble signals from the wobble pattern; generating wobble window signals indicative of a wobble window period which comprises a window width condition based on the phase-locked looped wobble signals; detecting whether the wobble signals exist during the wobble window period; generating wobble lock/unlock signals setting one of a wobble unlock state when the wobble signals do not exist and satisfy a preset wobble unlock condition and a wobble lock state when the wobble signals do exist and satisfy a preset wobble lock condition; counting the wobble window signals in response to the wobble lock/unlock signals indicating that the wobble signals do not exist during the wobble window period; detecting a wobble defect in response to the counted wobble window signals satisfying a defect decision condition; and outputting a defect detection signal indicative thereof.
The present invention also provides for a method of receiving wobble signals indicative of a wobble pattern formed on an optical medium including: detecting whether the wobble signals exist during a wobble window period and generating wobble lock/unlock signals indicative thereof; counting the wobble window signals in response to the wobble lock/unlock signals indicating that the wobble signals do not exist during the wobble window period; detecting a wobble defect in response to the counted wobble window signals satisfying a defect decision condition; and outputting a defect detection signal indicative thereof.
The present invention also provides for an apparatus which receives a wobble signal indicative of a wobble pattern formed on an optical medium, including: a defect detector detecting whether a defect exists in the wobble pattern based upon the wobble signal; and a verifier which verifies data of a defective region of the optical medium corresponding to the wobble pattern in response to the defect existing.
These together with other objects and advantages, which will be subsequently apparent, reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.
REFERENCES:
patent: 6028828 (2000-02-01), Maeda
patent: 6088307 (2000-07-01), Fushimi et al.
patent: 6144627 (2000-11-01), Muto
patent: 6442116 (2002-08-01), Asano
patent: 1998-080166 (1998-11-01), None
patent: 2000-0006387 (2000-01-01), None
Nguyen Linh V
Samsung Electronics Co. LTD
Staas & Halsey , LLP
Tokar Michael
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