| 摘要 |
An optical head and an optical disk apparatus are disclosed which are small-sized, permitting the attainment of a high recording density. A laser beam emitted from a semiconductor laser is shaped into a collimated beam by a collimator lens, then is folded mirror at right angles by a folding mirror and enters a light converging type hologram. A collimated beam thus incident on the light converging type hologram is focused to form a light spot on a surface for focusing of a transparent light converging medium. The light thus focused as the light spot on the focusing surface passes through an aperture having a width smaller than the diameter of the light spot and leaks out as a near-field light to the exterior of the transparent light converging medium. A recording layer of an optical disk is irradiated with the near-field light to effect recording or reproduction of information.
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