Optical inspection system and method including accounting for variations of optical path length within a sample
US11035793B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 7, 2019 |
| Grant date | Jun 15, 2021 |
| Priority date | — |
| Expiry date | Mar 7, 2039 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/12
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An illuminator/collector assembly can deliver incident light to a sample and collect return light returning from the sample. A sensor can measure ray intensities as a function of ray position and ray angle for the collected return light. A ray selector can select a first subset of rays from the collected return light at the sensor that meet a first selection criterion. In some examples, the ray selector can aggregate ray intensities into bins, each bin corresponding to rays in the collected return light that traverse within the sample an estimated optical path length within a respective range of optical path lengths. A characterizer can determine a physical property of the sample, such as absorptivity, based on the ray intensities, ray positions, and ray angles for the first subset of rays. Accounting for variations in optical path length traversed within the sample can improve accuracy.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.