Air refractometer

US6559951B2 · kind B2 · utility

Assignees

• Kazumasa Kusaka, Director General of National Institute of Advanced Industrial Science and Technology, Ministry of Economy, Trade and Industry · JP
• Mitutoyo Corporation · JP

Inventors

• Jun Ishikawa · Yokohama, JP
• Morimasa Ueda · Yokohama, JP
• Hiroki Masuda · Gifu, JP
• Yutaka Kuriyama · Ibaraki, JP

Key dates

• Filing date: Mar 27, 2001
• Grant date: May 6, 2003
• Expiry date: Jun 10, 2021

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N2021/458
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An optical measuring light path formed by a vacuum-side laser beam (Pa) as a reference standard and an optical measuring light path formed by a gas-side laser beam (Pb) as a dimension to be measured are coaxially located sandwiching a movable end (optical transparent body 12) of a vacuum container (11) in order to satisfy Abbe's principle requiring linear disposition of the reference standard and the dimension to be measured in measurement direction, thereby reducing measurement error in measuring air refractive index and improving measurement accuracy therefor.