Method and apparatus for optically inspecting a magnetic disk
US8634070B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Feb 1, 2013 |
| Grant date | Jan 21, 2014 |
| Priority date | — |
| Expiry date | Feb 1, 2033 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/95
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In a method and apparatus for optically inspecting a magnetic disk, irradiating the surface of the sample with a light by rotating and moving the sample in the direction orthogonal to the center axis of the rotation, detecting the regular reflection light from the surface of the sample, detecting the scattered light in the vicinity of the regular reflection light from the surface of the sample by separating the scattered light from the regular reflection light, detecting the scattered light scattered in the direction at a higher angle with respect to the normal direction of the surface of the sample, and detecting the defects by processing the detection signal of the regular reflection light, the detection signal of the scattered light in the vicinity of the regular reflection light, and the detection signal of the scattered light in the high angle direction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.