Autocollimator with grating
US5995215A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 8, 1997 |
| Grant date | Nov 30, 1999 |
| Priority date | — |
| Expiry date | Jul 8, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/26
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical crossed grating is used to calibrate a conventional autocollimator operated with a single-frequency light source. Since a collimated monochromatic beam is diffracted at a number of well known angles after being reflected from the grating, an array of spots is formed on the detector surface that makes it possible to calibrate the autocollimator in a single operation. Because the angle of the diffracted light is determined only by the spacing in the grid, the calibration accuracy is insensitive to temperature variations and to the position of the grid on the sample stage. The calibration scaling values are calculated simply by measuring the spot spacings on the detector surface in relation to the diffraction angles corresponding to the grid spacing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.