INFORMATION RECORDING AND REPRODUCING DEVICE

摘要

PURPOSE:To keep a 0-th order light beam and a diffracted light beam in an appropriate focused state by changing the DC level of a focusing error signal in accordance with the 0-th order light beam taken as a light beam for reading information and the diffracted light beam. CONSTITUTION:As to the 0-th order light beam L0 which is taken as the beam for reading information to be made incident on a magneto-optical disk 10, the wave aberration Ab is made minimum and the light beam L0 is made in the appropriate focused state on the recording track formed area 10a of the disk 10 when the DC level V of the focusing error signal Sf is made V1'. As to the respective 2nd order diffracted light beams L2a and L2b taken as the light beam for reading information to be made incident on the disk 10, the wave aberration Ab is made minimum and they are made in the appropriate focused state on the recording track formed area 10a of the disk 10 when the DC level V of the error signal Sf is made V2' which is higher than the V1'.