Head with active fly height control

Abstract

An apparatus and method for evaluating surface characteristics of a recording disc prior to incorporation into a disc drive. A glide test system includes a glide test head supportable over the disc, the glide test head having a negative-pressure air bearing slider and a contact sensor which outputs a signal when the glide test head contacts a feature of the disc surface. The glide test head and the disc are characterized as opposing plates of a variable capacitor with a dielectric layer therebetween including at least a layer of air supporting the glide test head. A voltage source, operably coupled to the glide test head and the disc, applies a fly height control voltage across the capacitor to adjust the fly height of the glide test head. The disc surface preferably comprises a data region configured to magnetically store data as the disc is rotated and a texturized landing zone configured to support the disc drive read/write head when the disc is stopped. The voltage source accordingly applies a first fly height control voltage to maintain the glide test head at a first glide distance over the data region and a second fly height control voltage to maintain the glide test head at a second, greater glide distance over the landing zone.