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Low-coherence interferometer for contact lens surface metrology

Contact lens performance depends on a number of lens properties. Many metrology systems have been developed to measure different aspects of a contact lens, but none test the surface figure in reflection to subwavelength accuracy. Interferometric surface metrology of immersed contact lenses is complicated by the close proximity of the surfaces, low surface reflectivity, and instability of the lens. An interferometer to address these issues was developed and is described here. The accuracy of the system is verified by comparison of glass reference sample measurements against a calibrated commercial interferometer. The described interferometer can accurately reconstruct large surface departures from spherical with reverse raytracing. The system is shown to have residual errors better than 0.05% of the measured surface departure for high slope regions. Measurements made near null are accurate to lambda/20. Spherical, toric, and bifocal soft contact lenses have been measured by this system and show characteristics of contact lenses not seen in transmission testing. The measurements were used to simulate a transmission map that matches an actual transmission test of the contact lens to lambda/18. (C) 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)

Identiferoai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/621479
Date29 March 2016
CreatorsHeideman, Kyle C., Greivenkamp, John E.
ContributorsUniv Arizona, Coll Opt Sci, Raytheon Space and Airborne Systems, 2000 East El Segundo Boulevard, El Segundo, California 90245, United States, University of Arizona, College of Optical Sciences, 1630 East University Boulevard, Tucson, Arizona 85721, United States
PublisherSPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS
Source SetsUniversity of Arizona
LanguageEnglish
Detected LanguageEnglish
TypeArticle
Rights© 2016 Society of Photo-Optical Instrumentation Engineers
Relationhttp://opticalengineering.spiedigitallibrary.org/article.aspx?doi=10.1117/1.OE.55.3.034106

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