| 摘要 |
PURPOSE: To obtain an information recording and reproducing device having compatibility with plural kinds of optical disks by changing over tracking error signals while judging the class of an optical disk. CONSTITUTION: An optical dusk 13 or an optical disk 14 used exclusively for a reading whose track pitches are 1.6μm, 0.8μm, etc, are irradiated with irradiation lights split into a main beam and two sub-beams with a diffraction grating 3 and reflected lights are detected with optical detectors 7. A tracking detecting means 16 generates a first tracking error signal being the difference between two sub-spot outputs and a second tracking error signal basing on the phase comparison between sums of respective two spots of quadri-sected main spots based on detection results. Then, the first and the second tracking error signals are selected with respect to respective disks 13, 14 by a disk discriminating means 8 and a changeover means 10 and then this device is made to be the information recording and reproducing device having compatibility with disks of two kinds whose track pitches or track forms are different, etc., by using the same optical head.
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