Optical checking method and apparatus for defects in magnetic disks
US8208356B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 22, 2010 |
| Grant date | Jun 26, 2012 |
| Priority date | — |
| Expiry date | Jan 6, 2031 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2220/2516
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An apparatus for optically checking magnetic disk defects that makes possible more accurate determination of positions of minute defects by illuminating an area greater than a checkup area with an illuminating beam having a Gaussian distribution is to be provided. The apparatus is configured of a specular reflection detecting device including a detector having a detecting face including an array of multiple pixels, and a processing device that figures out the position of each defect by using, in addition to the output signal from each of the pixels of the detector that detected a specular reflection from the checkup area, also output signals of some pixels out of the multiple pixels having detected the specular reflection from the checkup area of one turn before and the checkup area of one turn after, both adjoining in the radial direction, and determines the type of the defect.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.