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Scanner for Opaque Samples

IP.com Disclosure Number: IPCOM000080740D
Original Publication Date: 1974-Feb-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 3 page(s) / 108K

Publishing Venue

IBM

Related People

Hayes, LP: AUTHOR

Abstract

This device provides noncontact inspection of two-dimensional surfaces using a laser beam and moving mirror for the basic scan in combination with a specially placed lens, so that the light reflected from the sample being scanned can be uniformly retrieved for analysis across the field. The scanning beam is caused to intercept the planar surface of the sample at "normal" incidence across the field. Hence, the reflected light as modified by the character and reflectivity of the sample being scanned, will return to the source where it can be intercepted for analysis.

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Scanner for Opaque Samples

This device provides noncontact inspection of two-dimensional surfaces using a laser beam and moving mirror for the basic scan in combination with a specially placed lens, so that the light reflected from the sample being scanned can be uniformly retrieved for analysis across the field. The scanning beam is caused to intercept the planar surface of the sample at "normal" incidence across the field. Hence, the reflected light as modified by the character and reflectivity of the sample being scanned, will return to the source where it can be intercepted for analysis.

Appropriately expanded and collimated beam 1 (Fig. 1) from laser 2 passes through splitters 3, 4 and is incident on rotating mirror 5. As mirror 5 moves, the beam scans a line on lens 6. Since lens 6 is exactly one focal length from the rotating mirror 5, the emerging beam will at all times remain exactly normal to planar surface 7 of sample 8. Moreover, since sample surface 7 is exactly one focal length from lens 6, the beam will converge to focus in it.

The second dimension is generated with a mechanical table 9 (Fig. 2) having guided movement in an axis perpendicular to the scan line. Position sense is achieved by simultaneously scanning a precision sense grid 10 with a beam split by splitter 11 from the same source. The beam is polarized by 11a, 11b and oriented such that the orthogonal components are separated equally by splitter 11 and incident on planar surface 7 and s...