| 摘要 |
PURPOSE:To reduce the size and to decrease the access time, by a simple constitution that the beam spot condensed with the optical system from one piezoelectric resonator through the use of two resonance modes is oscillated in two axial directions. CONSTITUTION:An optical system block 17 including semiconductor legs and condenser lenses is fitted on a resonator for wobbling. The resonator 18 has two orthogonal oscillations in up and down direction and lateral direction, a part is cut with a slope, and one piezoelectric ceramic 19 is bonded to the surface, and two frequencies equal to each resonance frequency of the resonator 18 are produced at an oscillator 32 and fed. The laser light from an optical block 17 is condensed on a recording medium 1, and the phase change of the reflected light is detected and compared at a phase detector 33, allowing to know the shift from the track. Further, whether or not the focus is accurately oscillated up and down the recording pattern can be known. |
