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Proceedings Paper

Precision Focus Control
Author(s): Burton D. Figler
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Paper Abstract

The operational limitation on many high-resolution optical systems and, in particular, on high-resolution microdensitometers, is determined by the system's ability to establish and hold critical focus under dynamic conditions . A precision focus control, utilizing pneumatic actuation and feedback, is described which provides the needed dynamic focusing to permit the acievement of submicron optical resolution. This focus control system, although initially designed as an integral subsystem of the Aerodyne Linear Microdensitometer, has been incorporated as an add-on to PDS 1050 Microdensitometers and to the David Mann 10-47 Microdensitometer. The Precision Focus Control, in its standard configuration, has provided focusing accuracy to better than ±0.5 µm at disturbance frequencies to 10 Hz. The set focus position can be varied from slightly above the target surface to 25 µm below the target surface, while focus can be maintained over a range of surface variations of more than 1.5 mm. Because of the pneumatic pressure reacting against the object surface, local film hold-down is automatically provided without any mechanical contact of the object surface. Object thicknesses of up to 6 mm can be accommodated.

Paper Details

Date Published: 8 August 1978
PDF: 7 pages
Proc. SPIE 0141, Adaptive Optical Components I, (8 August 1978); doi: 10.1117/12.956511
Show Author Affiliations
Burton D. Figler, Aerodyne Research, Inc. (United States)

Published in SPIE Proceedings Vol. 0141:
Adaptive Optical Components I
Sandor Holly; Lawrence James, Editor(s)

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