Diffraction-based monitoring of a patterned magnetic recording medium
US6791784B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 23, 2001 |
| Grant date | Sep 14, 2004 |
| Priority date | — |
| Expiry date | Dec 14, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/59677
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The diffraction-based monitoring techniques described herein can be used, for example, as quality assurance measure in manufacture of magnetic recording media with servo tracking. In one embodiment, the invention presents a system comprising a light source such as a laser that directs light upon a surface of a magnetic recording medium. The magnetic recording medium has two or more physical marks, and the light striking the magnetic recording medium produces a diffraction pattern. A light detector such as a photodiode detects some or all of the diffraction pattern. The physical marks may be servo tracks on the magnetic recording medium, and the detected diffraction pattern is a function of the characteristics of the servo tracks.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.