Defect detecting optical apparatus enabling recording in an alternate sector or track

An optical recording/reproducing apparatus comprising:

• a disc-shaped recording medium for recording information therein, said recording medium having a plurality of tracks formed thereon, each of said tracks being divided into a plurality of sectors for recording information;
• a laser for emitting a light beam;
• laser driving means for controlling irradiation of the light beam from said laser to said recording medium in accordance with information to be recorded;
• optical means for passing the light beam emitted from said laser to a track on said recording medium, and for directing the light beam reflected from said recording medium;
• detection means for detecting the light beam reflected from said recording medium and directed through said optical means;
• circuit means for providing a signal representative of an amount of digression of the light beam from a desired track for one of a recording operation and a reproducing operation being performed on the basis of an output signal from said detection means;
• servo means for positioning the light beam on the center line of said desired track, in response to an output signal from said circuit means;
• comparator means for comparing the output signal from said circuit means with a predetermined level, and for delivering an output signal from said circuit means is greater than the predetermined level;
• first control means responsive to said comparator means for providing an output signal when the duration time of a predetermined state in an output signal of said comparator means exceeds a first predetermined time shorter than a time necessary for off-track of the light beam;
• second control means responsive to said comparator means for providing an output signal when the duration time of a predetermined state in an output signal of said comparator means exceeds a second predetermined time longer than said first predetermined time and sufficient to cause off-track;
• gate means responsive to the output signal from said first control means for inhibiting the application of a signal corresponding to information to be recorded in said recording medium to said laser driving means;
• and
• controller means responsive to the first control means for enabling information which has been inhibited from being recorded when said first control means provides the output signal, to be recorded on another sector of the same track, and said controller means responsive to the second control means for enabling recording of the information on another track in response to the output signal from said second control means.

A method of optically recording information comprising the steps of:

• passing a light beam to a desired one of a plurality of tracks formed on a disc-shaped recording medium, each of said tracks being divided into a plurality of sectors for recording information;
• detecting light reflected from said recording medium;
• generating a tracking error signal indicating an amount of digression of the light beam from a track where information is recorded and reproduced on the basis of the result of light detection;
• comparing the tracking error signal with a predetermined level;
• preventing projection of a recording light beam onto the recording medium so as to interrupt a recording operation when a time during which the level of the tracking error signal exceeds the predetermined level exceeds a first predetermined time shorter than a time necessary for off-track of the light beam;
• preventing projection of a recording light beam onto the recording medium to interrupt a recording operation when a time during which the level of the tracking error signal exceeds the predetermined level exceeds a second predetermined time longer than the first predetermined time and sufficient to cause off-track;
• enabling information, the recording of which has been interrupted when the first predetermined time is exceeded, to be recorded on another sector of the same track;
• and
• enabling information, the recording of which has been interrupted when the second predetermined time is exceeded, to be recorded on another track of the recording medium.