Flynn, Thiel, Boutell & Tanis, P.C.
Optical information medium
An optical information medium is made up of a transparent substrate for a reproducing laser beam to penetrate therethrough, a recording layer formed on the transparent substrate and a reflective layer for reflecting the reproducing laser beam thereupon, thereby enabling the recording of optically readable signals by a recording laser beam incident upon the transparent substrate. This optical information medium has a spiral-like tracking guide on a side surface of the transparent substrate, on which the recording layer is formed, and on lands defined between the spiral-like tracking guide are formed land pre pits indicative of the sector information, including the address and so on, wherein the length of the land pre pits is selected to be from 50% to 83% of the length of the minimum pit and to be from 1.5 to 2.5 times the length of the channel clock. Also, the film thickness of the recording layer in the area of the land pre pits is selected to differ from the film thickness of the recording layer in the area of the tracking guide.
Taiyo Yuden Co., Ltd.
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G11B G11B G11B G11B
inventional inventional inventional inventional
Ryou Toru Emiko Toshiaki
Negishi Fujii Hamada Tajima