| 摘要 |
PURPOSE:To attain a track survo with high accuracy by providing plural electrode plates on the trailing surface of the rail of the opposite side to the rail having a magnetic element, and measuring a track dislocation with a capacity change depending on the facing area between the electrode plate and concentric capacitance patterns. CONSTITUTION:An electrode plate 5 is provided at the rail on the side different from the rail possessing an element 4, the electrode 5 is constituted as three electrode plates 7, 8 and 9, which are separated respectively, on the front surface of a magnetic disk 10, grooves are formed concentrically, and respective possesses flat top parts 11 and flat bottom parts 12. In such a position relation, the electrode plate 8 is grounded, and the relative position relation between the head and the disk can be obtained with the aid of the polarity and the size of the difference of the capacities between the electrode plate 7 and the electrode plate 8, and the electrode plate 8 and the electrode plate 9. Thus, the signal of a track dislocation quantity can be obtained by the capacity change, and by feeding back the signal to the driving system of the head positioning device, the track servo with the high accuracy can be attained. |
