Fibre optic sensor with bonded dye

• US 4,560,248 A
• Filed: 08/09/1982
• Issued: 12/24/1985
• Est. Priority Date: 08/14/1981
• Status: Expired due to Term

• Current Assignee: Imperial Chemical Industries PLC (IMPERIAL CHEMICAL INDUSTRIES)
• Original Assignee: Imperial Chemical Industries PLC (IMPERIAL CHEMICAL INDUSTRIES)
• Inventors: Murray, Robert T., Cramp, John H. W., Reid, Robert F., Mortier, Roy M.
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Healy, Brian M.
• Application Number:
  US06/406,521
• Time in Patent Office: 1,233 Days
• Field of Search: 128/630, 128/632, 128/633, 128/634, 128/636
• US Class Current: 385/12
• CPC Class Codes: G01N 2021/7713 in core
• CPC Class Codes: G01N 2021/7716 in cladding
• CPC Class Codes: G01N 21/7703 using reagent-clad optical fibres or optical waveguides using measurement of total internal reflection or attenuated total reflection G01N21/552; optical fibres or waveguides per se G02B
• CPC Class Codes: G01N 21/80 Indicating pH value

Abstract

For detecting changes in chemical or physical parameters an optical fibre core has bonded to its surface a chromophore responsive to the parameter. The core preferably has a porous surface with the chromophore coating extending into the porous structure.

Claims

1. An optical sensor comprising an optical fibre core and a sensitive chromophore chemically bonded to the surface of the said core, the chromophore being variable in colour, in response to changes in a predetermined chemical or physical parameter, in combination with fibre optic means for launching light into the sensor and for collecting the light after it has been transmitted through the sensor;

whereby on being passed through the sensor, light is modified according to the colour response of the chromophore to the parameter to which the chromophore is sensitive.

2. A sensor as claimed in claim 1 wherein the surface is of a porous material and includes at least some of the surface area within the pores.

3. A sensor as claimed in claim 2 wherein the core comprises a non-porous portion surrounded by a porous layer to which the chromophore is bonded.

4. A sensor as claimed in claim 3 wherein the porous layer is integral with the non-porous portion.

5. A sensor as claimed in claim 3 wherein the optical fibre core is a composite of a non-porous material surrounded by and in intimate contact with a layer of porous material.

6. A sensor as claimed in claim 1, wherein the chromophore is a dye molecule whose colour is responsive to the parameter.

7. A sensor as claimed in claim 6 wherein the parameter is pH.

8. A sensor as claimed in claim 1, wherein the material forming the surface to which the chromophore is bonded is a silicate glass, and the chromophore is bonded to the glass through an intermediate silane coupling agent comprising a silane functional group with affinity for the glass and a group reactive with the chromophore.

9. A sensor as claimed in claim 8 wherein the chromophore is a dye molecule linked to the silane coupling agent via a triazine ring.

10. A sensor as claimed in claim 1 and forming a terminal portion of the fibre optic probe.