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AssigneeTaiyo Yuden Co., Ltd.
InventorsToru Fujii, Toshiaki Tajima, Yuji Tomizawa, Ryou Negishi, Emiko Hamada
Estimating the term…
An optical information recording medium enables accurate tracking servo throughout the recording area including inner and outer peripheral region by way of reducing the differences between the amplitudes of the push-pull signals from those regions. The medium comprises a light transmitting substrate, a tracking groove formed on a surface of the light transmitting substrate, a recording layer formed on the surface of the substrate having the groove, and a reflective layer, formed on the recording layer, for reflecting recording and reproducing laser beams. The width of the groove at the outer peripheral region is made smaller than that at the inner peripheral region. Specifically, the ratio of the width at the outer peripheral region to that at the inner peripheral region is set to be greater than or equal to 0.8.
An optical information recording medium for recording optically readable signals thereon by using a laser beam, comprising:
A light transmitting substrate, having a tracking groove formed on a surface thereof, to be used in manufacturing an optical information recoding medium having a recording layer formed on the surface having the tracking groove, wherein a width W1 of the tracking groove at an inner peripheral region of the substrate is greater than a width W2 at an outer peripheral region of the substrate,
A stamper for forming a light transmitting substrate, having a tracking groove formed on a surface of the light transmitting substrate, to be used in fabricating an optical information recording medium having recording layer formed on the surface having the tracking groove, comprising a land corresponding to the tracking groove of the light transmitting substrate, the land being formed on the stamper, wherein a width W1 of the land at an inner peripheral region of the stamper is greater than that a width W2 of the land at an outer peripheral region of the stamper,
Dependencies are inferred from the claim text.