Method for refocusing an optical assembly
US10393582B2 · kind B2 · utility
Assignees
Inventor
Key dates
| Filing date | Dec 22, 2015 |
| Grant date | Aug 27, 2019 |
| Priority date | — |
| Expiry date | Dec 22, 2035 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/1717
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method refocuses on an optical assembly target surface, using at least one beam originating from a short-pulse optical source, having at least one optical system for focusing the beam on the surface. Refocusing occurs after learning reference conditions for which the assembly is considered as focused. A focusing signal is detected representing a time overlap of pulses between a beam reflected and a reference beam not reflected by the surface, one of the beams delayed by a delay line. The optical path on which the delay line is placed is varied, on the basis of the reference conditions, to cause the focusing signal to reach or exceed a predetermined threshold. The focus is adjusted on the basis of the path variation between the reference conditions and the conditions for which the focusing signal reaches or exceeds the threshold.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.