OPTICAL INFORMATION RECORDING AND REPRODUCING DEVICE

PURPOSE:To prevent servo deviation of a light beam by extracting an AC component from the output of an optical sensor to detect abnormality and keeping the light beam in the position before the occurrence of abnormality by this detection signal to scan it. CONSTITUTION:The reflected light from a rec...

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Bibliographic Details
Main Author SHIKICHI SATOSHI
Format Patent
LanguageEnglish
Published 03.12.1991
Subjects
INFORMATION STORAGE
INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER
PHYSICS
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Summary:PURPOSE:To prevent servo deviation of a light beam by extracting an AC component from the output of an optical sensor to detect abnormality and keeping the light beam in the position before the occurrence of abnormality by this detection signal to scan it. CONSTITUTION:The reflected light from a recording medium is detected by optical sensors 101 and 103, and servo error signals generated from output signals of these sensors 101 and 103 are used to perform the servo control of tracking/ focusing. AC component extracting circuit 30 and 32 are provided which extract AC components from outputs of optical sensors 101 and 103 to detect abnormality, and the light beam is kept in the position before abnormality detection by this abnormality detection signal and is scanned. That is, the light beam is kept in the position before a defect and is scanned if there is the defect on a track. Thus, off-track is prevented regardless of the defect on the track to satisfactorily perform the recording and reproducing operation.
Bibliography:Application Number: JP19900068297