Surface characteristic determining apparatus

Jiang, Xiang, Wang, Kaiwei, Martin, Haydn and Yang, Shuming (2007) Surface characteristic determining apparatus. WO2007144654.

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Abstract

Light from the first and second different wavelength light sources is combined and supplied to a director that directs zeroth order light to a reference surface and other order, generally first order diffracted light to on a location of the sample surface which is dependent upon wavelength. Light reflected by the sample and reference surfaces interfere. A characteristic of a sample surface is determined from interference light of the first wavelength. Interference light of the second wavelength is used to enable phase-locking by adjusting the path length difference by moving the reference surface or changing the refractive index of a path portion to compensate for phase variation due to environmental effects.; Non- mechanical scanning is used to scan the sample surface by using a variable wavelength source and a director providing different first order diffraction angles for different wavelengths or an acousto-optical device that provides a variable pitch acoustic diffraction grating.

Item Type:	Patent
Subjects:	T Technology > TA Engineering (General). Civil engineering (General)
Schools:	School of Computing and Engineering School of Computing and Engineering > Centre for Precision Technologies School of Computing and Engineering > Centre for Precision Technologies > Surface Metrology Group
Related URLs:	Author Author
Depositing User:	Cherry Edmunds
Date Deposited:	20 Nov 2008 15:18
Last Modified:	02 Dec 2010 12:26
URI:	http://eprints.hud.ac.uk/id/eprint/2743

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