| 摘要 |
PURPOSE:To simplify eccentricity correcting structure of an optical disk medium remarkably by additionally providing an eccentricity detector that detects the position of boundary line between an information recording area and blank part of a light disk medium and an inducing mechanism that moves an optical head according to disk eccentricity information from the detector. CONSTITUTION:The principal part of the detecting system, i.e. the eccentricity detector 3 is provided with a light source 3b, a coupling lines 3c, a beam splitter 3d, an objective lens 3e and a light detector 4 consisting of a bisectional diode provided in the image forming zone 3a. By inputting eccentricity information of a light disk mesium 1 obtained by the eccentricity detector 3 to a rectilinear motor 10 through a compensating circuit 7, the rectilinear motor 10 shifts an optical head 8 on a carriage 9 in radial direction fo the medium 1, that is, in the direction shown by arrow mark A-A'. Accordingly, the optical head 8 becomes possible to be positioned always on a desired track guide groove (PG)1'.
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