Dual beam laser inspection apparatus
US4643569A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 18, 1985 |
| Grant date | Feb 17, 1987 |
| Priority date | — |
| Expiry date | Jun 18, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/112
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical input beam is split into first and second beams lying in first and second non-parallel planes. A polygon mirror scanner receives the first and second beams on a single facet and generates first and second angularly displaced, non-parallel synchronized scans. Redirecting means is positioned in the optical path between the scanner and a scanned plane for redirecting a portion of the first and second synchronized scans onto a timing plane to generate third and fourth non-coincident, synchronized scans. A beam position signal consisting of equally spaced, sequential pulses is generated in response to the travel of either the third or fourth synchronized scan along a second scanned line lying within a timing plane. The beam position signal is representative of the position of both the first and second synchronized scans along the first scanned line. The second section of the laser inspection apparatus reads information from a surface having an area illuminated by the dual beams of the optical scanner. The first and second synchronized scans from the optical scanner cause the illuminated area to emit radiation in the form of first and second modulated scans. Segmented radiatio…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.