OPTICAL AXIS ADJUSTMENT SYSTEM FOR OPTICAL PICKUP LENS

摘要

PURPOSE:To attain the alignment between a laser beam axis and an optical axis of a converging lens by moving an adjustment spot to a position of point symmetry of a reference spot with respect to the center position of an image pickup device and moving the adjustment spot to the center position by a distance moved by the reference spot in this case. CONSTITUTION:The position of a converging lens 3 is adjusted so as to move the adjustment spot A1 up to a position A2 in point symmetry of the reference spot B1 with respect to the center O. In this case, the reference spot B1 is moved in following to the movement of the adjustment spot A1 and since the movement quantity is a half the movement of the adjustment spot A1 in XY direction, the reference spot B1 is moved up to the B2 position. In this state, the adjustment spot A2 is moved toward the center O by the same distance as the movement of the reference spot from the B1 to B2. Thus, the adjustment spot A3 is overlapped with the reference spot B3 and the optical axis of the converging lens 3 is made coincident with the laser beam axis.