Compact interferometric test system for ellipses
US5929992A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 11, 1998 |
| Grant date | Jul 27, 1999 |
| Priority date | — |
| Expiry date | Aug 11, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/255
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus for testing elliptical mirrors is provided which reduces the length of the test apparatus by half, provides for precise location of the focus of the interferometer beam, and precise measurement of the distance between foci of the elliptical mirror under test. A small reflective sphere (10) with an optical passageway (15) through its center is used to locate the focal point (f.sub.2) of the interferometer (5) within interferometric precision. A plane mirror (30) is placed half way between the focal points of the ellipse (20) under test with one of the elliptical foci coincident with the interferometer focal point (f.sub.2). The elliptical mirror (20) under test is placed with reflective concave surface facing away from the interferometer (5) to receive light reflected from the plane mirror (30). The optical passageway (15) is sized to emit a volume of light to fill the elliptical mirror surface (22) after reflection from the plane mirror (30). The optical passageway (15) is also sized for the sphere (10) to reflect substantially all of the light incident upon it from the ellipse (20).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.