| 摘要 |
PURPOSE:To rerecord information while erasing information by irradiating an information erasing condensed spot in advance of irradiation of an information recording spot. CONSTITUTION:An objective lens 14 is supported by a voice coil movably in the direction of the optical axis and the radial direction of this voice coil; and when the objective lens 14 is placed in a prescribed position, beam waists of converging laser lights L1 and L2 discharged from the objective lens 14 are projected onto the surface of an information recording medium 15. Thus, two condensed spots different in length, namely, a shorter (l1) information recording and reproducing condensed spot (information recording condensed spot) 17 and a longer (l2) information erasing condensed spot 18 are formed with the center interval (d) spaced on an information recording track 16 of an information recording medium 15 moving a prescribed speed V so that the former precedes the latter with respect to time. |
