Title:
【発明の名称】空気の屈折率および光路長の影響を測定するための干渉測定器および方法
Document Type and Number:
Japanese Patent JP3332367
Kind Code:
B2
Abstract:
Apparatus and methods particularly suitable for use in electro-optical metrology and other applications to measure and monitor the refractive index of a gas in a measurement path and/or the change in optical path length of the measurement path due to the gas while the refractive index of the gas may be fluctuating due to turbulence or the like and/or the physical length of the measuring path may be changing. More specifically, the invention employs electronic frequency processing to provide measurements of dispersion of the refractive index, the dispersion being substantially proportional to the density of the gas, and/or measurements of dispersion of the optical path length, the dispersion of the optical path length being related to the dispersion of the refractive index and the physical length of the measurement path. The refractive index of the gas and/or the optical path length effects of the gas are subsequently computed from the measured dispersion of the refractive index and/or the measured dispersion of the optical path length, respectively. The information generated by the inventive apparatus is particularly suitable for use in interferometric distance measuring instruments (DMI) to compensate for errors related to refractive index of gas in a measurement path brought about by environmental effects and turbulence induced by rapid stage slew rates.
Inventors:
Degrute, Peter
Hill, Henry A.
Demarest, Frank Sea.
Hill, Henry A.
Demarest, Frank Sea.
Application Number:
JP2000532684A
Publication Date:
October 07, 2002
Filing Date:
February 18, 1999
Export Citation:
Assignee:
Zygo Corporation
International Classes:
G01B9/02; G01J9/02; G01N21/45; (IPC1-7): G01N21/45; G01B9/02
Domestic Patent References:
| JP1090175A | ||||
| JP9318310A | ||||
| JP7225114A | ||||
| JP62233704A |
Other References:
【文献】米国特許4685803(US,A)
【文献】米国特許44733967(US,A)
【文献】米国特許44813783(US,A)
【文献】米国特許44733967(US,A)
【文献】米国特許44813783(US,A)
Attorney, Agent or Firm:
Shusaku Yamamoto