| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pickup apparatus which is simple, low cost, and in which light utilization efficiency is high and unnecessary light causing disturbance is not generated. <P>SOLUTION: In the optical apparatus provided with a semiconductor laser 1, a polarization rotating element 2 which can rotate a polarization direction of a light beam in the direction of desired polarization by a signal from the outside, a dichroic half mirror 4 in which efficiency of transmission or reflection is different depending on a polarization direction, and a polarization hologram element 6 in which a convergence state of an emitted light beam is varied in accordance with a polarization state of an inputted light beam, a polarization direction of the optical beam emitted from the polarization rotating element 2 in a first optical disk 12 and a second optical disk 17 of which the width of disk substrates are different are set so as to be different almost 90 degrees with respect to an optical axis of the light beam. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
