Patent ID: 6956804

Claim:
An optical recording medium, including a reflective layer and a recording layer, and constructed in a manner that a recording mark is formed on the recording layer by irradiating a laser beam so as to record information, the recording layer being formed with plural virtual recording cells, each of which has an arbitrary unit length and a unit width perpendicular to the unit length, the unit length of a virtual recording cell being associated with an allowable irradiation time T of a laser beam securable to the virtual recording cell, the laser beam having a reference power, which is preset so that an optical reflectance of the virtual recording cell is reduced more than 50% with respect to an initial reflectance, the optical reflectance of the virtual recording cell is modulated into five stages or more by the laser beam within the allowable irradiation time T, the virtual recording cell being formed with a recording mark which gives five stages or more different optical reflectance to the virtual recording cell, wherein the virtual recording cell is capable of changing the optical reflectance, during a time period between 3/4 T and 4/4 T of the allowable irradiation time T, less than 20% and more than 5% of the initial reflectance.