Characterizing powders using frequency-domain photon migration
US6771370B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 21, 2002 |
| Grant date | Aug 3, 2004 |
| Priority date | — |
| Expiry date | Oct 21, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/8592
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Characterizing a powder bed includes generating measurements by repeating the following. A location of the powder bed is illuminated with light having a time varying intensity with a resolution of less than one hundred nanoseconds. The particles scatter the light to alter the time varying intensity. The light propagates through a portion of the particles that defines a sampled volume. The light received from the powder bed is detected. The altered time-varying intensity of the light is measured to generate a time-dependent signal having a time-dependence that is less than or equal to a time-of-flight of a photon of the propagating light. An optical property is determined from the time-dependent signal, and a characteristic is determined from the optical property. The sampled volume is determined, and variance of the measurements is calculated. Uniformity of the powder bed is determined in accordance with the variance and the sampled volume.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.