Invention Grant
US08830480B2 Measurement apparatus 有权
测量装置

Measurement apparatus
Abstract:
The present invention provides a measurement apparatus which measures a distance between a reference surface and a surface to be measured, including a wavelength reference element configured to include a gas cell in which a plurality of types of gases having absorption lines different from each other are sealed, and a processing unit configured to set a wavelength of light emitted by a light source to a plurality of different wavelengths corresponding to a plurality of different absorption lines by using the wavelength reference element, control a phase detection unit to detect a phase corresponding to an optical path length between the reference surface and the surface to be measured for each of the plurality of different wavelengths, and perform processing of obtaining the distance.
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