Sony Corporation

Somei Endo

Manabu Sato

Toshihiro Akimori

Masayoshi Kanno

Optical recording medium and master disc for preparation thereof

An optical recording medium which can provide a wobbling signal at a sufficiently high level even if the track pitch is reduced to enhance the recording density. The recording medium can attain a practically adequate recording-reproducing characteristic such as jitter characteristic. The medium has a wobbling groove that has a depth falling within the range of &lgr;/2.90 n to &lgr;/2.15 n. Here, &lgr; is the wavelength of a light beam applied to record and reproduce signals and n is the refractive index of the substrate of the optical recording medium. The ratio of the width Wg of the wobbling groove to the track pitch Tp (Wg/Tp) falls within the range of 25.0% to 45.5%.

Optical recording medium having wobbling groove extending along the tracks

The mark length of each of pits forming together the pit train is made shorter than that of each of pits for a to-be-written signal normalized at the predetermined bit interval T. Also, the mark length of a shortest one of the pits forming together the pit train is set to 64.8 to 80.0% of the shortest mark length for the to-be-written signal normalized at the predetermined bit interval T.

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Miyagi, Japan

Somei Endo