| 摘要 |
PURPOSE:To attain miniaturization and also the drive independently an objective lens in three directions by arranging a control coil in three directions in one magnetic air gap, forming the control coils in a dogleg shape, and arranging a forward path in the magnetic air gap and arranging the return of the outside of the magnetic air grip through four slit notches provided to the yoke. CONSTITUTION:Tracking coils 15a-15d folded in chevron shape and tangential coils 16a-16d are fitted to four slits 14a-14d by each four and a ring from focus coil 17 of ring form is wound to the outer circumference. The focus coil 17 and the forward paths 22a-22d, 23a-23d of the tracking coils 15a-15d and the tangential coils 16a-16d are arranged in the air gap of the magnetic circuit and their return paths 24a-24d, 25a-25d are led out of the air gap through the notches 21a-21d. Thus, the objective lens is driven independently in three directions. |
