| 摘要 |
PURPOSE:To shorten the access time by using the 1st and 2nd sliders which move linearly toward the radius of a disk, putting the minimum number of members necessary for constitution of an optical head and giving independent control to the positions of both sliders. CONSTITUTION:An end of each of two parallel springs 26 is fixed to the 1st slider 4, and an objective lens 10 and a focus coil 22 are supported at the other end of each spring 26. While a permanent magnet 23 and a yoke 24 are fixed to the 2nd slider 12 at the outside of the coil 22. The coil 22 conducts and gives vertical displacement to the lens 10 against a disk. Thus the slider 4 contains the optical elements including the lens 10 which constitute a photomagnetic optical system and other light-weight parts like an automatic focus detector, an automatic tracking detector, etc. While the slider 12 contains the magnet 23 for focus control, the yoke 24 and other primary members and an external signal line. Both sliders 4 and 12 are driven independently of each other. The light-weight slider 4 vibrates from a position A for control and stops at a position B after t3sec. While the heavy slider 12 reaches the point A later than the slider 4 and stops at the position B after vibration of a long time. In such a way, the access time can be shortened.
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