Interferometric flying height measuring device including an addition of a spacer layer
US5473431A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 29, 1993 |
| Grant date | Dec 5, 1995 |
| Priority date | — |
| Expiry date | Apr 29, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/14
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A device for accurately measuring flying heights of a read/write head 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. An interference pattern is obtained by reflecting a first portion of the light off of the top surface of the disk and reflecting a second portion of the light off of the underside of the read/write head, and then recombining the first and second portions of light. The interference pattern is then input to a spectrophotometer, which creates an intensity profile from which the flying height of the read/write head above the disk may be calculated. A spacer layer is provided on the upper surface of the disk to increase the phase difference of the first and second portions of light, thereby allowing clear interpretation of the interference pattern at extremely low flying heights.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.