| 摘要 |
PROBLEM TO BE SOLVED: To provide an aberration compensating device capable of compensating both an astigmatism different in direction and size and an aberration caused by the tilt of an optical disk. SOLUTION: In the liquid crystal panel arranged in an optical pickup, transparent electrodes 22A and 22B are arranged opposedly to each other while sandwiching the liquid crystals and the electrodes are controlled by a liquid crystal panel control section 8. Either tow kinds of driving voltages Va and Vb having different amplitudes or a GND is applied to pattern electrodes 30 to 38 of the electrode 22A through an amplitude modulator 106 and a selection switch 108, a desired phase difference is given to light beams and as a result, astigmatism caused by an optical system is compensated. Similarly, either one of driving voltages Vc, Vd and Ve is applied to pattern electrodes 40 to 44 of the electrode 22B through an amplitude modulator 107, a desired phase difference is given to optical beams and the aberration caused by a radial tilt is compensated for. Thus, two kinds of aberration are simultaneously compensated by a single liquid crystal panel and the arbitrary directivity of astigmatism is facilitated by varying a driving pattern. |
