OSA's Digital Library

Virtual Journal for Biomedical Optics

Virtual Journal for Biomedical Optics


  • Editors: Andrew Dunn and Anthony Durkin
  • Vol. 8, Iss. 7 — Aug. 1, 2013

Measuring the lens focal length by laser reflection-confocal technology

Jiamiao Yang, Lirong Qiu, Weiqian Zhao, Rongjun Shao, and Zhigang Li  »View Author Affiliations

Applied Optics, Vol. 52, Issue 16, pp. 3812-3817 (2013)

View Full Text Article

Enhanced HTML    Acrobat PDF (607 KB)

Browse Journals / Lookup Meetings

Browse by Journal and Year


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools



A laser reflection-confocal focal-length measurement (LRCFM) is proposed for the high-accuracy measurement of lens focal length. LRCFM uses the peak points of confocal response curves to precisely identify the lens focus and vertex of the lens last surface. LRCFM then accurately measures the distance between the two positions to determine the lens focal length. LRCFM uses conic fitting, which significantly enhances measurement accuracy by inhibiting the influence of environmental disturbance and system noise on the measurement results. The experimental results indicate that LRCFM has a relative expanded uncertainty of less than 0.0015%. Compared with existing measurement methods, LRCFM has high accuracy and a concise structure. Thus, LRCFM is a feasible method for high-accuracy focal-length measurements.

© 2013 Optical Society of America

OCIS Codes
(120.0120) Instrumentation, measurement, and metrology : Instrumentation, measurement, and metrology
(180.1790) Microscopy : Confocal microscopy
(220.4840) Optical design and fabrication : Testing

ToC Category:
Instrumentation, Measurement, and Metrology

Original Manuscript: February 5, 2013
Revised Manuscript: April 23, 2013
Manuscript Accepted: April 24, 2013
Published: May 30, 2013

Virtual Issues
Vol. 8, Iss. 7 Virtual Journal for Biomedical Optics

Jiamiao Yang, Lirong Qiu, Weiqian Zhao, Rongjun Shao, and Zhigang Li, "Measuring the lens focal length by laser reflection-confocal technology," Appl. Opt. 52, 3812-3817 (2013)

Sort:  Author  |  Year  |  Journal  |  Reset  


  1. K. V. Sriram, M. P. Kothiyal, and R. S. Sirohi, “Direct determination of focal length by using Talbot interferometry,” Appl. Opt. 31, 5984–5987 (1992). [CrossRef]
  2. P. Singh, M. S. Faridi, and R. S. Sirohi, “Measurement of focal length with phase-shifting Talbot interferometry,” Appl. Opt. 44, 1572–1576 (2005). [CrossRef]
  3. F. Lei and L. K. Dang, “Measuring the focal length of optical systems by grating shearing interferometry,” Appl. Opt. 33, 6603–6608 (1994). [CrossRef]
  4. M. Thakurand and C. Shakher, “Evaluation of the focal distance of lenses by white-light Lau phase interferometry,” Appl. Opt. 41,1841–1845 (2002). [CrossRef]
  5. C. J. Tay, M. Thakur, L. Chen, and C. Shakher, “Measurement of focal length of lens using phase shifting Lau phase interferometry,” Opt. Commun. 248, 339–345 (2005). [CrossRef]
  6. Y. P. Kumarand and S. Chatterjee, “Technique for the focal-length measurement of positive lenses using Fizeau interferometry,” Appl. Opt. 48, 730–736 (2009). [CrossRef]
  7. Y. Xiang, “Focus retrocollimated interferometry for focal-length measurements,” Appl. Opt. 41, 3886–3889 (2002). [CrossRef]
  8. I. K. Ilev, R. W. Faaland, D.-H. Kim, R. H. James, and D. Calogero, “Innovative confocal laser method for exact dioptric power measurement of intraocular lens implants,” Chin. Opt. Lett. 6, 876–878 (2008). [CrossRef]
  9. I. Ilev, “A simple confocal fibre-optic laser method for intraocular lens power measurement,” Eye 21, 819–823 (2006). [CrossRef]
  10. I. K. Ilev, “Simple fiber-optic autocollimation method for determining the focal lengths of optical elements,” Opt. Lett. 20, 527–529 (1995). [CrossRef]
  11. D.-H. Kim, D. Shi, and I. K. Ilev, “Alternative method for measuring effective focal length of lenses using the front and back surface reflections from a reference plate,” Appl. Opt. 50, 5163–5168 (2011). [CrossRef]
  12. J.-j. Wu, J.-b. Chen, A.-c. Xu, X.-y. Gao, and S. Zhuang, “Focal length measurement based on Hartmann–Shack principle,” Optik 123, 485–488 (2012). [CrossRef]
  13. J. Yang, L. Qiu, W. Zhao, and H. Wu, “Laser differential reflection-confocal focal-length measurement,” Opt. Express 20, 26027–26036 (2012). [CrossRef]
  14. T. Wilson, “Confocal microscopy,” in Confocal Microscopy, T. Wilson, ed. (Academic, 1990), Chap. 1, pp. 1–64.

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited