INTERFEROMETRIC FLYING HEIGHT MEASURING DEVICE

摘要

A device for measuring flying heights of a read/write head (30) in a disk drive down to zero microinches using interferometry, wherein the flying height of the head above the disk surface is calculated by directing white light to the under side of a rotating disk (20). A thin metallic layer (22) on the disk acts as a beam splitter, reflecting a first portion of the beam back downward, and allowing a second portion of the beam to pass therethrough to be reflected back downward off of the bottom surface of the read/write head. Once reflected, the two portions will combine to form an interference pattern. This pattern is then input to a spectrometer, which creates an intensity profile to represent the unique height of the air-bearing slider (36) above the beamsplitter layer. The flying height is finally determined by subtracting from this height the thickness of the spacer layer (24).