Method of making disk bumps with laser pulses for calibrating PZT sliders
US5528922A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 27, 1994 |
| Grant date | Jun 25, 1996 |
| Priority date | — |
| Expiry date | Dec 27, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49995
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method is provided for making crater shaped bumps on a calibration disk which can be used for calibrating a PZT slider, the PZT slider in turn being used for detecting predetermined asperities on a production run magnetic disk. The crater shaped bumps emulate predetermined asperities of production run magnetic disks and especially asperities which are undesirable and would cause the production run disk to be discarded after testing by the PZT slider. Crater shaped bumps which emulate undesirable asperities on current production runs of magnetic disks have a diameter in the range of 10 to 25 .mu.m and a peripheral ridge with a height h.sub.r above a nominal surface of the calibration disk in the range of 75 to 120 nm. Close tolerance crater shaped bumps with this configuration can be made by impinging two or more pulses of laser energy on the same location of a calibration disk. By increasing the number of pulses the height of the peripheral ridge progressively increases. By employing multiple pulses, the height of the peripheral ridge is increased while the diameter of the crater shaped bump stays substantially constant. Further, by employing multiple pulses diameters and heights…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.