Magnetic disk drive having a function for using a thermal protrusion amount for flying height management and an inspection device having such a function
US7330324B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 12, 2004 |
| Grant date | Feb 12, 2008 |
| Priority date | — |
| Expiry date | Jul 12, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/607
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A write head's material having a great thermal expansion coefficient expands due to Joule heat resulting from a write current and a temperature rise dependent on high-frequency core loss, thereby causing the head's flying surface to protrude toward a magnetic disk. This phenomenon is called TPR (thermal protrusion). It is essential that the flying height be accurately determined and managed in consideration of TPR. A magnetic disk drive for actual use or a magnetic disk drive that is in a testing process but similar to the one for actual use is used to measure TPR amount changes resulting from a write operation, store the resulting measured data in a memory or on the magnetic disk, and perform flying height management with the stored measured data. Further, flying height management is performed as needed in conjunction with a SMART function. The present invention makes it possible to perform high-reliability flying height management.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.