Variable-speed scanning for interferometric measurements
US5726754A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 30, 1996 |
| Grant date | Mar 10, 1998 |
| Priority date | — |
| Expiry date | Aug 30, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/026
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method of operation of a scanning mechanism that produces multiple constant-speed translations within the scanning range of operation. According to one aspect of the invention, when the instrument translates over a region where useful fringes are substantially absent, such as over the steep portion of a step discontinuity, the scanner is quickly accelerated to a higher constant speed and collection of intensity data is stopped until it reaches a new region of observable fringes. The scanner then is quickly decelerated to a slower constant speed and acquisition of intensity data resumes. According to another aspect of the invention, the position of the scanner during the nonlinear transition between regions of different constant speeds is determined by applying a transition factor based on the rate of acceleration (or deceleration) during the transition period. A practical transition factor is advantageously determined by assuming constant acceleration (or deceleration) during each transition between periods of constant-speed operation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.