| 摘要 |
PURPOSE:To enable a single optical system to have a recording and a reproducing function over tracking, by allotting recording and reproduction, and focusing and tracking to two light beams differing in wavelength respectively. CONSTITUTION:A beam B32 of a recording signal Er from a laser diode 32 is supplied to a polarizer 40 and then to a recording and reproducing pickup 50 through a dichroic mirror 46 to form its image on the recording surface of a recording medium disk 56. A beam B20 from a laser diode 72 is reflected by a mirror 46 and passed through the pickup 50 to form its image on the recording surface of the disk 56. The pickup 50 has a focus servomechanism and a track servomechanism, and the mirror 46 allows the beam B32 with the 1st waveform to pass it through, but reflects the beam B20 with the 2nd wavelength. |
