| 摘要 |
PURPOSE:To improve detection precision and work efficiency by moving a magnetic bubble back and forth in the same 'Permalloy(R)' pattern to allow the magnetic bubble to pass an optional point on the 'Permalloy(R)' pattern at least twice in difference directions and extracting even subtle defects which cannot be extracted by passage in the same direction. CONSTITUTION:The current flowing to a driving coil 2X has a waveform 1, and that flowing to a driving coil 2Y has a waveform 2, and a rotating magnetic field HR is moved as shown by a figure 3. If the waveform of the current flowing to the driving coil 2Y is changed at a half period of the waveform of the current flowing to the driving coil 2X as shown in the figure and is converted to a triangular wave which flows always in the same direction from a positive pole to a load or from the load to the positive pole, the rotating magnetic field HR is not rotated once but is rotated clockwise at 180 deg. to return to the original state after rotating counterclockwise at 180 deg.. Thus, a magnetic bubble B is moved back and forth between points (a) and (b) on a 'Permalloy(R)' pattern P.
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