| 摘要 |
PURPOSE:To stabilize a focus control by a simple structure, by providing in parallel the laser diode arrays of an elliptical spot and a circular spot, and photodetecting a light beam of one of them, in a recording device of a phase change type disk. CONSTITUTION:When the first laser diode array 1b is oscillated, an elliptical beam is projected onto a recording medium D, the recording medium which has become a molten state once is cooled by the elliptical beam, and a recording track which has become a crystallized state is formed. On the other hand, a circular beam from the second diode array 1a which is oscillated intermittently by an information signal irradiates intermittently immediately behind a recording track which is formed by the elliptical beam, a part of an amorphous state is formed on the recording track, and information is recorded. A four split photosensor 10 photodetects only a write beam which is reflected from the surface of a disk, therefore, a stable focus control, etc. can be realized. |
