| 摘要 |
PURPOSE:To attain an easy control method for an optical image pickup device with a simple constitution by making a collimator lens and plural cylindrical lenses independently controllable, respectively. CONSTITUTION:A disk or a mirror set opposite to an objective lens 5 is first deflected large, and a cylindrical lens 7 is shifted by means of a screw 19 to ward an axis (x) and fixed at the positive peak of an focus error signal F. Then a cylindrical lens 8 is also shifted toward the axis (x) and fixed at the negative peak of the signal F. Thus the coincidence is obtained between the optical axis of the beam and a photodetector 9 in the two directions within a plane vertical to the optical axis. Then a screw 16 is unfastened, and eccentric drivers are put into holes 14 and 15 to move a holder 11 for collimator lens, and the screw 16 is fixed at a position where the level of the signal S corresponding to the RF signal is maximum at the zero-cross point O of the signal F. Thus a spot having optical roundness is obtained on the detector 9. |
