Method and apparatus for detecting defects in transparent materials
US4725139A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 8, 1985 |
| Grant date | Feb 16, 1988 |
| Priority date | — |
| Expiry date | May 8, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/8845
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method of detecting defects present at the surface and/or internally in transparent materials, particularly of detecting included foreign bodies or bubbles in glass, is disclosed. The test material is scanned with an electromagnetic radiation of a single wavelength which is set to the penetration depth in the test material. The intensity reflected by the defects is picked up and analyzed. By this method only defects located up to a specified depth in the material are detected. Visible light as well as UV- or IR radiation may be applied. The associated test rig comprises a tunable Laser (2), a conveyor belt (6) carrying the test material (5), a fast rotating mirror-wheel (3) which directs the light beam (4) at high speed over the test material (5), and an optical sensor (7) connected with an analyzer unit (8).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.