| 摘要 |
In an optical head of a DVD drive, a light-emitting device and light-receiving devices are disposed on one face of a substrate, and on the other face of the substrate, a diffraction light separating device, a lambda/4 plate, and a dielectric plate having a converging focus lens are sequentially, hierarchically integrated. With the configuration, a laser beam (transmission beam) emitted from the front light-outgoing end of the semiconductor laser device sequentially passes through the diffraction light separating device, lambda/4 wave plate, and dielectric plate having the converging focus lens to form an image on a recording face of a recording medium (optical recording medium). A reflected beam reflected by the recording face returns reversely along the optical path through which the transmission beam has traveled, the phase of the reflected beam is changed by the lambda/4 wave plate, and the phase-changed reflected beam is separated into two primary diffracted beams in two directions. The primary diffracted beams fall on the light-receiving faces of the respective light-receiving devices. As a result, information can be reproduced and/or recorded by near-field recording.
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