DEVICE FOR MEASURING VERTICAL DISTANCE BETWEEN TWO OBJECT AND DEVICE FOR CONTROLLING SAID VERTICAL DISTANCE

摘要

PURPOSE: To determine the accurate vertical distance between two points of two objects not relatively but absolutely by providing a first conductive pattern having an edge extending vertically to the direction of relative motion between first and second objects. CONSTITUTION: A circuit 44 measures the electrical capacity between a first pattern on a disc 10 and a second pattern 30 on a slider 12 when the first pattern scans the second pattern 30. A circuit, 46 generates a signal proportional to the vertical distance between objects 10, 12 and processes electrical measurement signals from the circuit 44. Furthermore, the flying height of slider 12 can be measured at different radial positions of slider 12 using a step motor 58. A comparator 77 subtracts a reference signal from the vertical distance signal to generate a difference signal from the reference signal. A height actuator 80 for increasing/decreasing the height of slider 12 is regulated based on the output from a height controller 78.