Method and apparatus for recording/reproducing by pre-pits detection
AssigneesHtachi, Ltd., Hatachi Video & Information System, Inc.
InventorsToshimitsu Kaku, Toru Kawashima, Takehiko Sekine, Hisataka Sugiyama, Yosiho Suzuki, Tetsuya Fushimi
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Abstract
A beam is irradiated to an information recording medium having land tracks and groove tracks alternately formed on a track formed in turn on an information recording surface thereof and pre-pits so pre-formatted as to deviate from the center of the track, a return beam of the irradiated beam is received by detectors split into two parts in a track direction to obtain a differential signal, the pre-pit is detected from this differential signal and control of recording and reproducing processings is executed by using the pre-pit detection signal so obtained as the reference.
Claims9
An information recording and reproducing apparatus comprising:
- pre-pit detection means for irradiating a beam onto an information recording medium having land tracks and groove tracks formed alternately in a track on an information recording surface thereof, and having pre-pits pre-formatted in such a manner as to deviate from a center of said track;
- detectors for receiving a reflected beam of said irradiated beam, split into two parts in the track direction to obtain a differential signal;
- pre-pit detection means for detecting pre-pit portions from said differential signal without decoding of pre-pit signals, and generating pre-pit detection signals;
- and
- means for controlling recording and reproducing processing using said pre-pit detection signals as a reference.
Apparatus for reproducing information recorded in a recording medium having land track portions and groove track portions alternately formed in a track on an information recording surface thereof, and having pre-pits pre-formatted therein and deviating from a center of said track, said apparatus comprising:
- means for focusing a detection beam onto said recording surface;
- means for detecting a beam reflected from said recording surface and for generating a detection signal indicative thereof;
- means for splitting said detection signal into two parts to obtain a differential signal;
- means for detecting recorded pre-pit portions by detecting polarity of said differential signal;
- and
- means for controlling reproducing processing using signals indicative of detection of said pre-pit portions as a reference.
Dependencies are inferred from the claim text.