Interference objective lens unit and light-interference measuring apparatus using thereof
US8553232B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 24, 2011 |
| Grant date | Oct 8, 2013 |
| Priority date | — |
| Expiry date | Feb 16, 2032 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B9/0209
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Disclosed is an interference objective lens unit, comprising: an objective lens; a beam splitter that splits the light transmitted through the objective lens into a reference optical path in which a reference mirror is provided and a measuring optical path in which the measuring object is placed, and that superposes the split lights to output interference light; a first holder that holds the objective lens and that is formed by material having a first linear expansion coefficient; and a second holder that holds the reference mirror and that is formed by material having a second linear expansion coefficient different from the first linear expansion coefficient, wherein when a usage environment temperature changes, a difference in the linear expansion coefficients between the first holder and the second holder corrects an optical path difference between the reference optical path and the measuring optical path.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.