Optical information recording medium and apparatus for recording/reproducing information using the same

An apparatus for recording or reproducing information on or from a card-shaped optical information recording medium comprising tracking tracks each of which is formed as an unbroken line and clock tracks, at least a portion of each of said clock tracks being formed as a line intermittently broken at constant periods, each arranged alternately and record zones in which information is to be recorded and each of which is provided between each of the tracking tracks and each of the clock tracks so that only one of each of the tracking tracks and each of the clock tracks is alternately positioned between two adjacent record zones, said apparatus comprising:

• means for forming at least first, second, and third beam spots on said recording medium;
• means for projecting said first spot on the record zone to record or reproduce informaiton;
• tracking signal detection means for projecting one of said second and third beam spots on the tracking track to detect a tracking signal;
• means for changing over said tracking signal detection means in accordance with the positional relation between said projected record zone and the tracking track so as to obtain the tracking signal from the other one of said second and third spots;
• and
• clock signal detection means for projecting the remaining spot of the second and third spots, which is not projected on said tracking track, on the clock tract to detect a clock signal.

An apparatus for recording and reproducing information using a card-shaped optical information recording medium comprising tracking tracks each of which is formed as an unbroken line and clock tracks each of which is formed as a line intermittently broken at constant periods, said tracking tracks and clock tracks each being arranged alternately, and record zones in which information is to be recorded and each of which is provided between each of the tracking tracks and each of the clock tracks so that only one of each of the tracking tracks and each of the clock tracks is alternately positioned between two adjacent record zones, said apparatus comprising;

• means for producing and projecting at least three beam spots on the recording medium, said producing and projecting means projecting said beam spots on the record zone, the tracking track and clock track, respectively, at the time of recording to write information in said record zone while detecting a tracking signal and a clock signal, and said producing and projecting means projects said beam spots on the tracking track and two or more record zones respectively at the time of reproduction to simultaneously read out the recorded information in said two or more record zones while detecting the tracking signal;
• tracking signal detection means for detecting the tracking signal from the beam spot projected on the tracking track at the time of recording;
• means for changing over said tracking signal detection means in accordance with the positional relation between said projected record zone and the tracking track so as to always obtain the tracking signal from the beam spot projected on the tracking track at the time of recording;
• and clock signal detection means for detecting the clock signal from the beam spot projected on the clock track at the time of recording.