Straightness of travel interferometer
US4787747A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 13, 1987 |
| Grant date | Nov 29, 1988 |
| Priority date | — |
| Expiry date | Nov 13, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B2290/70
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An interferometer system capable of measuring accurately the deviations from straightness of travel comprises a source (10) of a frequency stabilized input beam (12) with two linear orthogonally polarized components which may or may not be of the same frequency; a tilted parallel plate or shear plate (16) with regions of reflection, antireflection, and polarizing coatings, for converting the input beam into two separated, parallel, orthogonally polarized beams (30, 31); a half-wave retardation plate (24), located in one of the separated beams (31), for converting the two separated, orthogonally polarized beams into first and second beams which are spatially separated, parallel, and have the same polarization (30, 33); a polarizing beamsplitter (40) and quarter-wave retardation plate (44) for transmitting the first and second beams (34, 35) to a prism assembly (45), attached to the mechanical apparatus whose straightness of travel is to be measured, for refracting the parallel first and second beams (36, 37) into diverging third and fourth beams (38, 39); a mirror assembly (70) with its surfaces (70 A, 70B) perpendicular to the third and fourth beams (38, 39) for producing convergin…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.