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Fluorescent Optical Position Sensor

Sandia National Laboratories

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Technology Marketing SummarySandia National Laboratories has created a method and apparatus for measuring the position of an object.  It relies on the attenuation of fluorescence light carried inside a fluorescent optical fiber to determine the position of an object. DescriptionAs show in the figure, a small excitation source, such as a laser or LED, excites a localized area of fluorescence at an unknown position along the fluorescent fiber.  As the fluorescent light travels down the fiber, the intensity of the fluorescent light decreases due to absorption.  The ratio of the two signals from each end determines the position of the object along the fiber. Appropriate modulation of the excitation source causes ambient light to be of no consequence and allows one to measure the position of several objects simultaneously with a single fluorescent fiber and a single set of photodectectors.  The flexibility of the fluorescent fiber allows for the determination of positional changes that do not occur along a straight line.  The use of an array of such fibers allows for the detection of two-dimensional changes in position. Benefits
  • Measures fluorescent light emitted from the waveguide
  • Does not introduce electrical energy
  • Insensitive to electromagnetic interference
  • Provides continuous measurements
  • Has few moving parts
Applications and Industries
  • Hazardous Environments
  • Oil and Gas Drilling
  • Mineral Drilling
  • Water Well Drilling
Patents and Patent Applications
ID Number
Title and Abstract
Primary Lab
Patent 6,965,709
Fluorescent optical position sensor
A fluorescent optical position sensor and method of operation. A small excitation source side-pumps a localized region of fluorescence at an unknown position along a fluorescent waveguide. As the fluorescent light travels down the waveguide, the intensity of fluorescent light decreases due to absorption. By measuring with one (or two) photodetectors the attenuated intensity of fluorescent light emitted from one (or both) ends of the waveguide, the position of the excitation source relative to the waveguide can be determined by comparing the measured light intensity to a calibrated response curve or mathematical model. Alternatively, excitation light can be pumped into an end of the waveguide, which generates an exponentially-decaying continuous source of fluorescent light along the length of the waveguide. The position of a photodetector oriented to view the side of the waveguide can be uniquely determined by measuring the intensity of the fluorescent light emitted radially at that location.
Sandia National Laboratories 11/15/2005
Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated
Patent# 6,965,709/ SD# 7144Prototype - Sandia estimates this technnology at approximately TRL 5. Key elements have been demonstrated in relevant environments. Available - Various licensing and partnering options are available. Please contact the Intellectual Property Department to discuss.07/20/201103/12/2013

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