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Method of Measuring Contours in Organic Material

IP.com Disclosure Number: IPCOM000122096D
Original Publication Date: 1991-Oct-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 1 page(s) / 54K

Publishing Venue

IBM

Related People

Goodman, D: AUTHOR

Abstract

In the well-known light-section method, a slit or array of slits is imaged onto the object whose contour is to be determined. By observing the intersection of the slit image with the object, the contour can be found. If the surface is sufficiently diffuse, the observation can be made in a direction normal to the surface, which is often preferable since an entire area can be seen in focus. If the surface reflectance is principally specular, the observation can only be made in the direction of the specular reflection. This viewing angle allows only a single line to be in focus, making measurements and identification difficult.

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Method of Measuring Contours in Organic Material

      In the well-known light-section method, a slit or array of
slits is imaged onto the object whose contour is to be determined. By
observing the intersection of the slit image with the object, the
contour can be found. If the surface is sufficiently diffuse, the
observation can be made in a direction normal to the surface, which
is often preferable since an entire area can be seen in focus. If the
surface reflectance is principally specular, the observation can only
be made in the direction of the specular reflection. This viewing
angle allows only a single line to be in focus, making measurements
and identification difficult. If the surface is specular and the
range of reflectance angles is sufficiently great, the reflected
light is not gathered by the observation optics, so the contour
cannot be determined by the standard light section method with any
viewing direction. In this case, other optical techniques, e.g.,
interferometry, are likewise subject to difficulties.

      The present invention provides a means for finding the surface
contour if the surface is specular and if the surface is made of
material that fluoresces, even if there is considerable irregularity
in height. This is done by projecting a slit at a wavelength at which
the surface fluorescences. The fluorescence is emitted in all
directions, so observation from any angle can be made. This method
can also be used with non-specular fluorescent su...