1 December 1973 Design Considerations for a Linear Microdensitometer
Author Affiliations +
Abstract
Tradeoff studies and tests on the various subsystems of a microdensitometer have resulted in a recommended design configuration for a Linear Microdensitometer. The photometric subsystem includes laser sources suitable for color operation, an illumination system capable of producing a 1 um spot on the film, a wide angle collection system (NA = 1.0), a photodiode detector, and digital density conversion. Performance of the photometric system was verified by breadboard tests. The results include an MTF (square wave response) of 99 percent at 200 Qp/mm and 90 percent at 500 kp/mm, and linearity (object independence) to greater than 400 Qp/mm. The photometric precision is ±0.01 D from 0 D to 2 D and ±0.02 D from 2 D to 4 D. These specifications are attained at scanning speeds up to 8000 samples per second. A two-beam optical system and automatic focus control ensure photometric repeatability. The two-axis stage is driven by phase-locked loop servos incorporating interferometric position sensors. The servos permit scanning at skew angles, obviating stage rotation. The stage sub-system is precise to within ±0.5 pm over 5 inches of travel. Stage speed is variable from 0.4 mm/sec to 40 mm/sec. Human factors features include rapid sample acquisition by virtue of a viewing system with magnification variable from 16X to 200X and simplified operator control through a CRT graphic terminal.
John P. Fallon, John P. Fallon, } "Design Considerations for a Linear Microdensitometer," Optical Engineering 12(6), 126206 (1 December 1973). https://doi.org/10.1117/12.7971663 . Submission:
JOURNAL ARTICLE
7 PAGES


SHARE
RELATED CONTENT

Target tracking and pointing for arrays of phase-locked lasers
Proceedings of SPIE (September 18 2016)
Precision pointing mechanism for laser communication mission
Proceedings of SPIE (October 11 1996)
Linear position sensor
Proceedings of SPIE (February 06 2006)

Back to Top