| 摘要 |
PURPOSE:To compensate the position deviation due to a temperature coefficient of components of an optical head by providing a light source of a 2nd laser optical system reading and erasing information onto a piezoelectric element connected to a 4-split detector detecting a reflected light. CONSTITUTION:A semiconductor laser 21 acting like a laser light source is fixed to a frame 23 by using an adhesives via a piezoelectric element 22 and the frame 23 is fixed to the optical head. A DC voltage is impressed to the electrode provided to both sides of the base 24 to expand/contract the base to adjust minutely the height of the semiconductor laser 21. In adding a feedback circuit to the detection circuit of read light in this way, the position deviation of focusing or tracking due to the thermal expansion or contraction is compensated. |
