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Proceedings Paper

Measurement of surface quality using a moire deflectometer
Author(s): Eliezer Keren; Kathi Kreske; Amiadav Livnat
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Paper Abstract

The ability of moire deflectometry to measure surface quality is compared to other optical probes. The comparison is done using the amplitude - wavelength (A - W) diagrams introduced by Stedman. Two modes of analysis allow the extension of the amplitude and wavelength ranges over many orders of magnitude. In the flatness mode, the actual profile is calculated from the fringe slopes using an adaptation of the phase shift method. The range of amplitudes covered by this mode is from around A = 100 nm (at wavelengths down to 50 jim) to over 100 jim at W = 50mm. In the roughness mode the autocovariance function is calculated from measurements of fringe contrast versus sensitivity (or shear) of the instrument. Resolution extends to several nanometers of amplitude and a few microns in wavelength. The tunable sensitivity of the moire deflectometer allows a considerable overlap between the flatness and the roughness modes of operation. Both fringe shifts and contrast are measured from the same deflectogram thus yielding a dynamic range much wider than those of other optical methods. The above figures refer to the Rotlex Optics OMS -400 which is a general purpose instrument. The A -Wranges may be extended in certain directions by building more specialized instruments based on the same technique. However, such extensions may reduce the range in other portions ofthe A -W space. The method is demonstrated using various types of surfaces.

Paper Details

Date Published: 1 August 1990
PDF: 8 pages
Proc. SPIE 1266, In-Process Optical Measurements and Industrial Methods, (1 August 1990); doi: 10.1117/12.20279
Show Author Affiliations
Eliezer Keren, Rotlex Optics Ltd. (Israel)
Kathi Kreske, Rotlex Optics Ltd. (Israel)
Amiadav Livnat, Rotlex Optics Ltd. (Israel)


Published in SPIE Proceedings Vol. 1266:
In-Process Optical Measurements and Industrial Methods
H. A. Macleod; Peter Langenbeck, Editor(s)

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