Apparatus and method for optical inspection of articles
US5450201A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 8, 1994 |
| Grant date | Sep 12, 1995 |
| Priority date | — |
| Expiry date | Feb 8, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B21/0016
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Apparatus for optically inspecting an article, includes an illuminating system, an imaging system, and portable polarizing devices including a polarizer in the illuminating system, an analyzer in the imaging system, and a phase compensator in one of the systems. The illuminating system directs the light from the light source to the objective lens along an axis which is parallel to, but is laterally displaced from, the axis of the objective lens, such as to illuminate the inspected article with a cone of light which is tilted at an angle relative to the axis of the objective lens to thereby permit contrast enhancement of the illuminated inspected article by the null-ellipsometric effect.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.