ABSTRACT In this paper, a fiber optic displacement sensor with a new reflectivity compensation method is presented. The proposed compensation method is based on two light receiving channels with characteristic displacement sensitivities. The sensitivity characteristic for each channel is achieved by using fibers with different numerical apertures. The ratio of the intensity values of the two receiving channels is a function of the object displacement and fairly independent from the reflectivity of the measured object. The sensor is characterized by a well-defined measurement spot. By use of a focus lens mounted onto the fiber optics probe head, the object displacement range can be extended. The sensor is suitable for measurements with changing object reflectivity and demanding distance ranges.
Cite this paper
A. Wego and G. Geske, "Fiber Optic Displacement Sensor with New Reflectivity Compensation Method," Journal of Sensor Technology, Vol. 3 No. 2, 2013, pp. 21-24. doi: 10.4236/jst.2013.32004.
 W. E. Frank, “Detection and Measurement Device Having a Small Flexible Fiber Transmission Line,” US Patent No. 3273447, 1966.
 C. D. Kissinger, “Fiber Optic Proximity Probe,” US Patent No. 3327584, 1967.
 C. D. Kissinger, “Fiber Optic Proximity Instrument Having Automatic Surface Reflectivity Compensation,” US Patent No. 4247764, 1981.
 C. D. Kissinger and R. Dormann, “Reflectivity Compensating System for Fiber Optic Sensor Employing Dual Probes at a Fixed Gap Differential,” US Patent No. 4488813, 1984
 L. Hoogenboom, “Fiber Optic Proximity Sensors for Narrow Targets with Reflectivity Compensation,” US Patent No. 4701610, 1987.
 C. D. Kissinger, “Reflectivity Compensated Fiber Optic Sensor,” US Patent No. 4701611, 1987.
 R. Hafle, “Fiber Optic Probe Sensor for Measuring Target Displacement,” US Patent No. 5017772, 1991.
 F. Suganuma, A. Shimamoto and K. Tanaka, “Development of a Differential Optical-Fiber Displacement Sensor,” Applied Optics, Vol. 38, No. 7, 1999, pp. 1103-1109.
 X. Li, K. Nakamura and S. Ueha, “Reflectivity and Illuminating Power Compensation for Optical Fibre Vibrometer,” Measurement Science and Technology, Vol. 15, No. 9, 2004, pp. 1773-1778.
 M. L. Casalicchio, G. Perrone, D. Tosi, A. Vallan and A. Neri, “Non-Contact Low-Cost Fiber Distance Sensor with Compensation of Target Reflectivity,” IEEE International Instrumentation and Measurement Technology Conference, Singapore, 5-7 May 2009, pp. 1671-1675.
 A. Wego and G. Geske, “Reflexionskompensierter Faseroptischer Abstandssensor,” Photonik, Vol. 17, No. 5, 2012, pp. 62-64.