Optical recording/reproducing apparatus capable of multi-track access for simultaneous multirack recording/reproduction

A method of simultaneously reproducing data of a plurality of tracks from an optical card having a large number of tracks thereon, using a multi-track type optical head for generating a light beam radiated on the plurality of tracks, comprising the steps of:

• (a) checking whether a distance difference between a track at which a central part of the light beam is currently located and a target track is not more than a given distance corresponding to a half of the number of the plurality of tracks;
• (b) when the checked distance difference is not more than the given distance, simultaneously reproducing addresses of the plurality of tracks at which the light beam is currently located, and when the checked distance difference is more than the given distance, further checking whether the checked distance difference is not more than a predetermined value which is not less than twice the given distance;
• and
• (c) when the twice-checked distance difference is not more than the predetermined value, moving the light beam in accordance with the twice-checked distance difference, and when the twice-checked distance difference is not less than the predetermined value, moving said optical head in accordance with the twice-checked distance difference, whereby an address of the target track is reproduced by said plurality of detection elements after the step (c) even if a moving distance of the light beam contains an error.

An apparatus for optically reproducing data recorded on a data recording medium having data recording tracks, the apparatus comprising:

• means for generating a light beam which simultaneously illuminates a plurality of tracks of said data recording tracks;
• detection means including a plurality of detection elements arranged in a line for receiving the light beam from the plurality of tracks and for detecting said data recorded on each of the plurality of tracks;
• and
• moving means for relatively moving the light beam across said data track, in response to a reproduction request of a target track, by a distance corresponding to a distance difference between a track at which a centrally located detection element of the plurality of detection elements and the target track, whereby data of the target track is detected by said plurality of detection elements even if a moving distance of the light beam contains an error.