| 摘要 |
PROBLEM TO BE SOLVED: To eliminate a noise from a regenerative signal when an optical disk having a wobbling groove is reproduced by shielding light reflected with the optical disk in a regenerative optical path system after passing through an objective lens. SOLUTION: A magneto-optical signal is obtained by differential detecting signals of photodiodes 16, 17. The signal is written in by a magnetic field modulation system by applying an AC magnetic field with a magnetic head 18 in the state irradiating the optical disk 5 with laser light. First, an EFM random signal of a minimum mark length 0.83μm is recorded on an MD by using the magnetic head 18. A standard deviation of a 3T signal at a clock 1T=230nsec of this recording signal is defined as jitters. As a shield band, a carbon rod with thickness 1mm is arranged at a nearly center of a beam of regenerative light. The jitters value is remarkably improved by shield band arrangement. |
