Patent ID: 6088306
Filing Date: 2000-07-11
Classification: G11B

Abstract:
An apparatus for writing and reading information on a rotatable disk which has at least one set of substantially parallel embedded tracks between which information is writable by laser means, said apparatus comprising:a source of laser radiation;first laser beam splitting means for receiving said laser radiation and producing therefrom a first laser beam for combined writing and reading, and a second laser beam for tracking;first mirror means for 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;means for oscillatorily moving said second laser beam in a direction back and forth across an edge of one of said tracks;means for 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;means for positioning said laser source in response to said position determination;second light beam splitting means receiving said first laser beam and splitting it into a beam for writing and a beam for reading wherein light beam output from said first and second beam splitting means is directed in different directions;second mirror means for 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 at a point on said disk behind points at which data is written; andmeans for detecting laser radiation from said reading beam which has been reflected from said disk.