# US 9,134,252 B2 · Head for an evanescent-wave fibre-optic sensor

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- Number: US 9,134,252 B2
- Document ID: US9134252B2
- Status: Granted
- Kind: B2
- Application number: 14/235,897
- Filed: 2012-06-12
- Published: 2014-08-21
- Granted: 2015-09-15
- Earliest claimed: 2011-07-29
- Assignees: Diafir
- Applicants: Hugues Tariel
- Inventors: Hugues Tariel
- Web page: https://patentgrep.com/patent/US9134252B2

## CPC

- G01N 21/8507: {Probe photometers, i.e. with optical measuring part dipped into fluid sample}
- G01J 3/0202: {Mechanical elements; Supports for optical elements}
- G01J 3/0218: {using optical fibers}
- G01J 3/42: Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry (beam switching arrangements G01J3/08)
- G01N 21/552: Attenuated total reflection
- G01N 21/3504: for analysing gases, e.g. multi-gas analysis
- G01N 21/3563: for analysing solids; Preparation of samples therefor
- G01N 21/3577: for analysing liquids, e.g. polluted water
- G01N 2021/8528: {Immerged light conductor}
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N)

## Abstract

The present invention relates to a head (500) for a sensor comprising two sections of optical fiber enabling the propagation of infrared light having at least one infrared wavelength and generating evanescent waves toward the outside in order to detect infrared signatures of an external medium, said head (500) comprising: an optical fiber forming a curved portion (15) for connecting the two sections of fiber, and for coming into contact with the external medium so as to detect the infrared signatures interfering with the propagation of the evanescent waves propagating along the fiber, and means (504, 506) for protecting the curved portion (15) against external mechanical stress, while ensuring that a contact area (30) exists between the external medium and said curved portion (15).

## Claims

### Claim 1

Head (500, 900) for a sensor (100) comprising two sections of optical fibre (11, 12) for propagating infrared light at at least one infrared wavelength and generating evanescent waves to the outside in order to detect infrared signatures of an external medium, said head (500, 900) comprising:
an optical fibre forming a curved part (15) intended to connect the two sections of fibre (11, 12) and to come into contact with the external medium in order to detect the infrared signatures interfering with the propagation of the evanescent waves propagating along the fibre, and
means (504, 506) intended to protect the curved part (15) against external mechanical stresses, while guaranteeing a contact area (30) between the external medium and said curved part (15),
wherein said means (504, 506) intended to protect the curved part (15) comprise a first plate (504) and a second plate (506) parallel to said first plate (504) and comprising a stud (502) with an axis which is perpendicular to said second plate (506), said first plate (504) comprising a flow conduit (508) intended to allow a flow of a liquid external medium between the plates (504, 506),
wherein said curved part (15) is placed between said first plate (504) and said second plate (506),
wherein said curved part (15) of the fibre comprises a turn wound around the stud (502), wherein each plate (504, 506) has two protrusions, each being designed to come opposite a protrusion on the other plate (506, 504), and in that one end of the curved part (15) is housed between each pair of protrusions.

### Claim 2 (depends on 1)

Head (900) according to claim 1, characterized in that each pair of protrusions comprises a rib (904) and a plane (906) that can be machined so as to form support surfaces in two different directions.

### Claim 3 (depends on 1)

Head (500) according to claim 1, characterized in that at least one plate (504, 506) comprises ribs (704, 706) that can be machined so as to form support surfaces in two different directions.

### Claim 4 (depends on 1)

Head (500, 900) according to claim 1, characterized in that said stud (502) is situated facing an opening of the flow conduit (508).

### Claim 5 (depends on 1)

Sensor (100) comprising:
a protective sheath (24) enclosing two sections of optical fibre (11, 12) for propagating infrared light at at least one infrared wavelength and generating evanescent waves to the outside in order to detect infrared signatures of an external medium,
a head (500, 900) according to claim 1, and
a connector (20) fixing the head (500, 900) on the protective sheath (24).

### Claim 6 (depends on 5)

Spectrometry system, characterized in that it comprises a sensor (100) according to claim 5.