| 摘要 |
PURPOSE: To prevent the collision between a probe and a medium and to prevent the deformation of the tip of the probe by constituting a probe position control mechanism so that the driving control central position of the driving mechanism can be biased by the offset signal of an offset generating means. CONSTITUTION: A tunnel current value JT, which flows out from a recording medium 102 through a probe 101, enters an error signal generating section 204. The section 204 computes the extent of the deviation from the probe recording medium separation set by a reference current value and outputs the signal corresponding to the deviation. The error signal is inputted to a minute control output generating section 202 which computes and outputs the amount of control for a minute motion mechanism 103 in accordance with the magnitude of the signal. Low frequency components of the outputted control amount are extracted through an LPF 205 and inputted to a coarse motion control output generating section 201 and a coarse motion mechanism 104 is driven in accordance with the amount. Furthermore, the amount of the control, which is the output of an output generating section 202, is added with the offset value generated by an offset generating section 203 by an adder 206 and is used to drive the mechanism 103.
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