US 8,542,353 B2 · Refractive index sensor for fluid analysis

Abstract

A refractive index sensor having one or more sources, an adaptive optical element or scanner, imaging optics, a sensing optic, and one or more detectors. The scanner impinges a signal from the source into the sensing optic and onto a sensor-sample interface at sequential angles of incidence. The detector response increases dramatically to signals reflected from the interface at corresponding sequential angles of reflection equal to or greater than a critical angle. The refractive index sensor also uses an input lens between the scanner and the sensing optic and uses an output lens between the sensing optic and the detector. A processor controls the sensor and can determine index of refraction of the fluid sample based on the detector response and scan rate. The sensor can be used in several operational environments from a laboratory to a downhole tool, such as a formation tester to determine properties in a borehole environment.

Claims35

Dependent claims

A refractive index sensor, comprising:

a source generating an input signal;
an adaptive optical element optically coupled to the source and routing the input signal at sequential angles;
a sensing optic optically coupled to the adaptive optical element and having an interface with a sample;
at least one detector optically coupled to the sensing optic and detecting one or more reflected signals from the interface, the one or more reflected signals indicative of any of the sequential angles of the input signal that are at least equal to or greater than a critical angle of reflection at the interface, the at least one detector optically coupled to the adaptive optical element and detecting at least one direct signal directly from the adaptive optical element;
and
a processor operably coupled to the at least one detector, the processor determining a refractive index value from the one or more reflected signals and the direct signal and correlating the refractive index value to a characteristic associated with the sample.

3 more elements

Dependencies are inferred from the claim text.

Refractive index sensor for fluid analysis

Life of this patent

Refractive index sensor for fluid analysis

Life of this patent

Abstract

Claims35