Active tracking method for optical disk storage
AssigneeInternational Business Machines Corporation
InventorsCasimer Maurice DeCusatis, Lawrence Jacobowitz
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Abstract
Laser light is focused in an accurate manner on selected tracks on an optical disk recording medium by means of an analysis of output electrical signals from a dithered light source which results in the production of an electrical signal which is proportional to an amount by which the light source in the system is to be moved, relative to the tracks, in order to achieve desired tracking of the focused spot along a desired track on the medium.
Claims6
A method for providing an electrical signal proportional to an amount by which a laser light source is to be moved relative to a track on a rotating information storage medium wherein the reflectivity of said storage medium in the region between tracks is different than the reflectivity along said tracks, said method comprising the steps of:
- moving said light source in an oscillatory fashion in a direction which crosses said track;
- converting light, from said light source, which has been reflected from said disk, into an electrical signal;
- and
- integrating said electrical signal over time for at least one period for said oscillatory motion.
Dependencies are inferred from the claim text.