Closed loop Foucault knife-edge test
US4993831A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 21, 1990 |
| Grant date | Feb 19, 1991 |
| Priority date | — |
| Expiry date | Mar 21, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01M11/0257
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The historical Foucault knife-edge test enables one to passively ascertain an optical imaging device's characteristics, for example, whether or not it is a source of optical aberrations. The historical Foucault knife-edge test corresponds to an open loop control system, since a control action, which is that quantity responsible for producing the imaging device characteristic, or open loop output, is independent of that output. The present invention, in sharp contrast to the historical Foucault knife-edge test, discloses a method for closing the Foucault open loop, so that the control action is somehow dependent on the output. In this way, accordingly, dynamic steps can be taken to compensate for, or remove the optical aberrations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.