Method and system for measuring a physical parameter of at least one layer of a multilayer article without damaging the article and sensor head for use therein
US6128081A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 27, 1997 |
| Grant date | Oct 3, 2000 |
| Priority date | — |
| Expiry date | Nov 27, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2291/0421
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and system are provided to measure a physical parameter of a film such as film thickness or build, in both the wet and dry states of the film, on an article in a production environment without any contact or damage to the film or the rest of the article. The system includes two laser light sources, one pulsed and the other substantially continuous (i.e. long pulses), an interferometer, fiber optic cables, and appropriate optics including multiplexers and demultiplexers to: 1) image and transmit light from both sources to the film on the article; and 2) transmit the light from the continuous source reflected off the film surface back to the interferometer, and a computer containing a data acquisition card to record the data after signal processing and appropriate software to process the data. Light from both light sources are imaged on and over the same spot on the surface of the film. The pulsed light source is used to generate ultrasound in the film. The reflected light from the continuous source is detected by the interferometer to probe the ultrasonic vibrations of the film. The motion of the surface of the film at ultrasonic frequencies generates a Doppler shift in the…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.