METHOD AND DEVICE FOR MEASURING SURFACE SHAPE

PURPOSE:To perform measurement of high accuracy in a short time by recording the intensity distribution of an interference pattern obtained when the phase of light wave of either a light from an object to be measured or a reference light is changed N times and finding the phase of the interference p...

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Bibliographic Details
Main Authors KUZE TSUTOMU, OSHIDA YOSHISADA, KAMIOKA TETSUYA
Format Patent
LanguageEnglish
Published 04.04.1984
Subjects
MEASURING
MEASURING ANGLES
MEASURING AREAS
MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS
PHYSICS
TESTING
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Summary:PURPOSE:To perform measurement of high accuracy in a short time by recording the intensity distribution of an interference pattern obtained when the phase of light wave of either a light from an object to be measured or a reference light is changed N times and finding the phase of the interference pattern at each sampling point. CONSTITUTION:Light of laser, etc., comes out from a coherence light source 1. Beams returned from an object 7 to be measured and another beam from a reference optical path interfere with each other at an interference pattern generating optical path 12 and the interference pattern is projected onto the image- pickup plane 15 of an image-pickup device 14 by an image-forming lens 13. The interference pattern is sampled at a fixed pitch and the intensity of interference patterns at each image-pickup sampling point is detected and sent to a control circuit 16. The control circuit 16 takes in N pieces of interference pattern intensity signals and stores them in an external memory 18 through a computer 17. The computer 17 finds the phase of interference patterns at all sampling points by using Fourier transform and measures the surface shape.
Bibliography:Application Number: JP19820168313