Data reading and/or writing apparatus of type using optical card

An apparatus for writing a data signal on an optical card which contains a number of track units, each including at least one prerecorded control track and an area on which a plurality of data tracks of a track unit may be written, said control and data tracks extending in parallel with each other in a first direction, the apparatus comprising an optical head including:

• a reading light source for emitting a reading light beam which is modulated in accordance with a data signal to be written on the optical card;
• a writing light source for emitting a writing light beam having a constant intensity;
• an optical system for projecting the reading light beam onto the optical card as a large spot having a diameter which is at least equal to a width of one of said track units and projecting the writing light beam onto the optical card as a small light spot having a diameter which is substantially equal to a width of one of said tracks;
• and
• photodetecting means including at least one control detector for receiving an image of said control track to derive a clock pulse;
• and
• driving means for moving the optical head and the optical card relative to each other in said first direction as well as a second direction perpendicular to said first direction;
• whereby the data signal is written on said plurality of data tracks of said track unit in synchronism with said clock pulse.

An apparatus for reading and writing a data signal out of and on an optical card which contains a number of track units, each including at least one prerecorded control track having control pits and extending in a first direction, and an area on which a plurality of data tracks may be written, each data track having data pits and extending in said first direction, comprising:

• a housing including a reading light source for emitting a reading light beam which is modulated in accordance with a data signal to be written on the card;
• an optical system for projecting the reading light beam onto the optical card as a large light spot having a dimension large enough for illuminating simultaneously a plurality of said pits of said control and data tracks of at least one of said track units;
• a writing light source for emitting a writing light beam having a constant intensity;
• an optical system for projecting the writing light beam onto the optical card as a small light spot having a diameter which is substantially equal to a width of one of said tracks;
• and photodetecting means including at least one control detector for receiving an image of said at least one control track to derive a clock pulse, said data signal being written on said plurality of data tracks of said track unit in synchronism with said clock pulse, said photodetecting means further including a plurality of data detectors for receiving images of said plurality of data tracks;
• driving means for moving the optical card and the housing relative to each other in said first direction as well as in a second direction perpendicular to said first direction;
• and
• data signal generating means for deriving said data signal by sampling output signals supplied from said plurality of data detectors in synchronism with said clock pulse.