Quality evaluation method, information recording medium, optical disc device and recording/reproducing system

An optical disc device, comprising:

• an optical pickup unit to irradiate a recording medium in a plurality of recording media with a light from a light source;
• a user data signal generation unit that generates a recorded waveform of the light irradiation for recording to record user data in a user data area on the recording medium;
• a signal processing unit that processes a reading signal from the optical pickup unit;
• and
• a particular pattern signal generation unit that determines a recorded waveform of the light to record a particular pattern outside the user data area, the particular pattern having a lifetime shorter than a reference lifetime of the user data, a particular pattern signal read by the signal processing unit when the particular pattern is irradiated by the optical pickup unit, a quality of the user data corresponding to a quality of the particular pattern signal,
• wherein the reference lifetime is an intermediate value in a user data lifetime distribution that corresponds to a lifetime value for which user data recorded on a percentage of the recording media in the plurality of recording media is preserved.

A recording/reproducing system, comprising:

• a recording medium in a plurality of recording media having a particular pattern recorded thereon, the particular pattern having a lifetime shorter than a reference lifetime of user data recorded in a user data area, the particular pattern recorded outside the user data area;
• an optical pickup unit to irradiate the recording medium with a light from a light source, a particular pattern signal read by the optical pickup unit when the particular pattern is irradiated;
• a user data signal generation unit that generates the recorded waveform of the light to record the user data;
• a quality evaluation unit to evaluate a quality of the particular pattern signal from the optical pickup unit and determine a quality of the user data based on the evaluated quality of the particular pattern signal;
• and
• a timing control unit to instruct the quality evaluation unit to evaluate the quality at an inspection time,
• wherein the reference lifetime is an intermediate value in a user data lifetime distribution that corresponds to a lifetime value for which user data recorded on a percentage of the recording media in the plurality of recording media is preserved.