| 摘要 |
An optical head (1) having an optical means for focusing a laser beam to irradiate an optical recording medium (51) is equipped with an objective lens (2) focusing a laser beam L, and a solid immersion lens (3) disposed between the objective lens (2) and the optical recording medium (51), the head comprising a holder member (4) for integrally retaining the lenses (2) and (3) and a moving mechanism (5a) for moving the holder member in a direction along an optical axis of the lenses (2) and (3), wherein an electrically conductive material is used on a surface of the optical head facing the optical recording medium (51). The numerical aperture can be made large by the solid immersion lens (3). Moreover, the air gap can be controlled with high precision according to the electrostatic capacity formed between the electrically conductive material and the optical recording medium (51). Furthermore, the moving mechanism (5a) and the signal processing for the focus servo operation can be made simpler.
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