Information recording medium and method of recording or reproducing optical information employing the same
AssigneeFuji Photo Film Co., Ltd.
InventorNorihisa Haneda
Life of this patent
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Abstract
An information recording medium including a disc-shaped substrate and a recording layer for optically recording and reproducing information with a laser beam where the recording layer is disposed on the substrate. The surface of the substrate is provided with a tracking guide including grooves having a depth of 200 to 600 angstroms and a width of 0.3 to 0.6 .mu.m. A method of optically recording information and a method of optically reproducing recorded information using the information recording medium are also disclosed.
Claims6
An information recording medium comprising a disc-shaped substrate and a recording layer provided thereon, wherein the substrate is provided on its surface with a tracking guide comprising grooves having a depth of 300 to 500 angstroms and a width between 0.3 .mu.m and 0.5 .mu.m, the recording layer has a plane surface having a high reflectance of not less than 60% and EFM signals of CD format are recorded in the recording layer on the grooves by irradiating the recording layer on the grooves with a laser having a wavelength in the range of 750 to 850 nm under rotating the recording medium at a fixed linear speed.
A method of optically recording and reproducing information on an information recording medium comprising the steps of:
- recording EFM signals of CD format on an information recording medium comprising a disc-shaped substrate and a recording layer provided thereon, wherein the substrate is provided on its surface with a tracking guide comprising grooves having a depth of 300 to 500 angstroms and a width between 0.3 .mu.m and 0.5 .mu.m and the recording layer has a plane surface having a high reflectance of not less than 60%, by irradiating the recording layer on the grooves with a laser having a wavelength in the range of 750 to 850 nm under rotating the recording medium at a fixed linear speed, and
- reproducing the recorded EFM signals of CD format by irradiating the recording layer on the grooves of the information recording medium with a laser beam by a three-beam tracking method using three beams which comprise a main beam for reading out the EFM signals and two sub-beams for tracking arranged before and after the main beam under rotating the recording medium at a fixed linear speed.
Dependencies are inferred from the claim text.