Optical information device and loss-of-control detection method

An optical information device which records information by converging a main beam and a sub beam on an information layer of an information recording medium, the device comprising:

• a focus control unit for performing control so that a convergent point of the main beam converges on a predetermined information layer;
• a tracking control unit for performing control so that the convergent point of the main beam scans a predetermined track or a predetermined mark sequence on an information layer;
• a sub beam receiving unit for receiving the sub beam reflected off the information layer and outputting a signal according to an amount of beam received;
• and
• a loss-of-control detection unit for detecting, during a recording operation of recording the information, a focus loss-of-control state where the convergent point of the main beam deviates from the predetermined information layer or a tracking loss-of-control state where the convergent point of the main beam deviates from the predetermined track or the predetermined mark sequence on the information layer, based on a signal from the sub beam receiving unit,
• wherein the sub beam includes a plurality of sub beams,
• the sub beam receiving unit includes a plurality of sub beam receiving units which respectively receive the plurality of sub beams reflected off the information layer, and
• the loss-of-control detection unit detects the focus loss-of-control state or the tracking loss-of-control state when a sum of levels of a plurality of signals output from the plurality of sub beam receiving units is a reflected light level from a recorded region where information is recorded or a reflected light level from an unrecorded region where information is not recorded.

A loss-of-control detection method in an optical information device which records information by converging a main beam and a sub beam on an information layer of an information recording medium, the method comprising:

• a focus control step of performing control so that a convergent point of the main beam converges on a predetermined information layer;
• a tracking control step of performing control so that a convergent point of the main beam scans a predetermined track or a predetermined mark sequence on an information layer;
• a sub beam receiving step of receiving the sub beam reflected off the information layer and outputting a signal according to an amount of beam received;
• and
• a loss-of-control detection step of detecting, during a recording operation of recording the information, a focus loss-of-control state where the convergent point of the main beam deviates from the predetermined information layer or a tracking loss-of-control state where the convergent point of the main beam deviates from the predetermined track or the predetermined mark sequence on the information layer, based on a signal output in the sub beam receiving step,
• wherein the sub beam includes a plurality of sub beams,
• in the sub beam receiving step, the plurality of sub beams reflected off the information layer are respectively received by a plurality of sub beam receiving units, and
• in the loss-of-control detecting step, the focus loss-of-control state or the tracking loss-of-control state is detected when a sum of levels of a plurality of signals output from the plurality of sub beam receiving units is a reflected light level from a recorded region where information is recorded or a reflected light level from an unrecorded region where information is not recorded.

An optical information device which records information on an information recording medium including a track in which mutually isolated recording regions are disposed in sequence, the device comprising:

• a recording unit for recording information in each of the recording regions;
• a resonance element of which resonance state changes according to a recording condition of the recording region;
• a tracking control unit for performing control so that the recording unit scans a predetermined track;
• a resonance state detection unit for detecting a change in the resonance state of the resonance element occurring according to the recording condition of the recording region, and outputting a signal according to the detected change in the resonance state;
• and
• a loss-of-control detection unit for detecting, during a recording operation of recording the information, a tracking loss-of-control state where the recording unit deviates from the predetermined track, based on a signal from the resonance state detection unit.

A loss-of-control detection method in an optical information device which records information on an information recording medium including a track in which mutually isolated recording regions are disposed in sequence, the method comprising:

• a tracking control step of performing control so that a recording unit for recording information in each of the recording regions scans a predetermined track;
• a resonance state detection step of detecting a change in a resonance state of a resonance element of which resonance state changes according to a recording condition of the recording region, and outputting a signal according to the detected change in the resonance state;
• and
• a loss-of-control detection step of detecting, during a recording operation of recording the information, a tracking loss-of-control state where the recording unit deviates from the predetermined track, based on a signal output in the resonance state detection step.