Apparatus for surface inspection
US5377001A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 14, 1992 |
| Grant date | Dec 27, 1994 |
| Priority date | — |
| Expiry date | Jul 14, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/1045
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
This apparatus permits the non-destructive examination of entire surfaces for defects and contamination, and can detect microscopically small dot-shaped and linear defects and extremely fine macroscopic non-homogeneous areas. For this purpose, an astigmatic lens system (5) is placed in the optical path between light source (2) and objective (9) which produces a cigar-shaped intermediate image (31), in which the feed offset in scanning the surface (10) depends on the intermediate image (31) and is equal to the length of the intermediate image (31) projected upon this surface (10). A dark-field stop assembly (18) with an adjustable dark-field deflection system (8) is placed in the optical path between the lens system (5) and the objective (9), which projects the light beam (1) after deflection exactly centered at right angles through the objective (9) upon the surface of the object (10). The light reflected by the surface (10) and collected by the objective (9) is projected to a photo detector. An electronic analysis system (21) breaks down the amplified output signals from the photo detector (19) into measured values due to dot-shaped, linear, and planiform defects. The electronic a…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.