Patent ID: 6097677
Filing Date: 2000-08-01
Classification: G11B

Abstract:
A method for writing and reading information on a rotating disk which has at least one set of substantially parallel embedded tracks between which information is writable by laser means, said method comprising the steps of:providing a laser beam light source;splitting said laser beam into a first beam for combined writing and reading operations and a second beam for tracking;directing said second laser beam towards said disk in a direction substantially parallel to said first beam and at a fixed distance from said first beam;moving said second laser beam in an oscillatory manner in a direction back and forth across an edge of one of said tracks;detecting laser radiation from said second beam which has been reflected from said disk, whereby the position of said second beam with respect to said track is determinable;positioning said laser source in response to said position determination;splitting said first beam into a beam for writing and a beam for reading, wherein said beam for writing and said beam for reading are directed along different paths;directing said reading beam towards said disk in a direction substantially parallel to said second beam and at a fixed distance from said second beam and at a point on said disk behind points at which data is being written to said disk by said beam for writing; anddetecting laser radiation from said reading beam which has been reflected from said disk.