| 摘要 |
PROBLEM TO BE SOLVED: To exactly discriminate the kind of disk at all the time without depending on the sensitivity, control voltage and current of an actuator. SOLUTION: Concerning this disk discriminating method, a pickup is perpendicularly moved to an optical disk while irradiating the optical disk with laser light from the pickup, a reflect signal 1 showing the focusing of laser light provided at that time on the surface of the optical disk and first and second peak signals 2 and 3 to appear before and after focusing the pit surface of the optical disk with the laser light are measured, first time 4 between the reflect signal 1 and the first peak signal 2 and second time 5 between the first and second peak signals 2 and 3 are found, the ratio 4/5 of these times is calculated and from this ratio calculated result, it is discriminated whether the optical disk is CD disk or DVD disk. The dispersion in the moving speed of the pickup caused by the dispersion in the sensitivity, control voltage and current of the actuator is absorbed by the said ratio calculation and the kind of disk can be exactly discriminated at all the time.
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