Information recording medium and method of recording or reproducing optical information employing the same

Claim 1

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 μm and 0.5 μm, 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.

Claim 5

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 μm and 0.5 μm 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.

Claim 6

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 μm and 0.5 μm 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.