Browse Prior Art Database

Opto Electronic System for Surface Profilometry

IP.com Disclosure Number: IPCOM000073666D
Original Publication Date: 1971-Jan-01
Included in the Prior Art Database: 2005-Feb-22
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Harrison, RW: AUTHOR

Abstract

The method described is for profiling a specular to semispecular surface without contacting the surface. The technique allows a high scanning rate and has sensitivity comparable to conventional stylus/electronic devices.

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Opto Electronic System for Surface Profilometry

The method described is for profiling a specular to semispecular surface without contacting the surface. The technique allows a high scanning rate and has sensitivity comparable to conventional stylus/electronic devices.

The optical system consists of a collimating lens 1 of a focal length f and a diameter sufficient to span the test surface 2. A slit source 3 of width W and a parallel knife edge 4 are positioned orthogonal to the optic axis of collimating lens 1 and positioned in the focal plane of collimating lens 1 by use of a bean splitter B/S-1. An objective lens 5 creates an image of the test surface 2 for the image scanner 6 and the ocular 12 by use of a second beam-splitter B/S-2. The ocular 12 is used for visual monitoring.

The electronic system consists of an image scanner 6 for repeatedly scanning the light intensity cross section of the image of the test surface 2 and converting this to an electrical signal. The scan line is orthogonal to the knife edge 4. An adjustable DC bias source 8 is used for setting the average scanning signal to zero. The gate pulse generator 7 conditions the operational amplifier integrator 9 during each scan. The operational amplifier integrator 9 processes the scan signal from the adjustable DC bias source 8 to provide the zeroth derivative profile y. The output of the image scanner 6 provides the first order derivative y' of the surface profile along the scan line. Display amplifiers 10 and 11 are used for driving a dual trace cathode...