US 5,332,316 AGranted

Fiber optic systems for sensing temperature and other physical variables

OwnerMarcos Y. Kleinermaninventor

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Abstract

The invention is drawn to methods and devices for measuring temperature with a simple probe, a single interrogating light source and a single photodetector in a manner that the same probe can be used for simultaneously sensing another physical parameter, using the same interrogating light source and the same photodetector. The invention also allows the use of a single probe for measuring temperature in two independent physical modes, using a single interrogating light source and a single photodetector. In a preferred embodiment the probe includes a photoluminescent material having a luminescence decay time which decreases substantially with increasing temperature over a temperature range within which its luminescence quantum efficiency remains approximately constant or varies only minimally.

Claims17

Dependent claims

A fiber optic device for sensing temperature changes in an object or environment, including:

(a) a probe comprised of photoluminescent material characterized by an ability to absorb a fraction .alpha.P.sub.o of the intensity P.sub.o of interrogating radiation of suitable pre-selected wavelengths injected into the probe and emit luminescence radiation of wavelengths .lambda..sub.1 different from the wavelength of the interrogating radiation and an intensity which varies as a known function of .alpha., where .alpha. is a fraction smaller than unity and increases with increasing temperature within at least part of the temperature range of operation of the device, said material including luminescence centers chosen from the group of 3d.sup.3 transition metal ions consisting of divalent vanadium, trivalent chromium and tetravalent manganese ions, the probe being further so characterized that, when excited with transient or periodic optical radiation of wavelengths within an absorption band of said material, it emits luminescence radiation with an intensity which decreases after termination of the excitation radiation with a decay time which decreases substantially with increasing temperature within a range of temperatures;
(b) a source of said transient or periodic optical radiation;
(c) fiber optic means for directing said transient or periodic optical radiation to said probe;
(d) fiber optic means for directing a fraction of the intensity of the luminescence radiation emitted from said probe to photodetector means;
and
(e) photodetector and associated electronic means for measuring the decay time of the luminescence emitted from said probe, said decay time being an indicator of the probe temperature.

3 more elements

An optical method for measuring the temperature of an object or environment, comprising the steps of:

(a) exposing a probe to the temperature to be measured, said probe including a photoluminescent material characterized by an ability to absorb a fraction .alpha.P.sub.o of the intensity P.sub.o of interrogating radiation of suitable pre-selected wavelengths injected into the probe and emit luminescence radiation of wavelengths .lambda..sub.1 different from the wavelength of the interrogating radiation and an intensity which varies as a known function of .alpha., where .alpha. is a fraction smaller than unity and increases with increasing temperature within at least part of the temperature range of operation of the device, said material including luminescence centers chosen from the group of 3d.sup.3 transition metal ions consisting of divalent vanadium, trivalent chromium and tetravalent manganese ions, the probe being further so characterized that, when excited with transient or periodic optical radiation of wavelengths within an absorption band of said material, it emits luminescence radiation with an intensity which decreases after termination of the excitation radiation with a decay time which decreases substantially with increasing temperature within a range of temperatures;
(b) illuminating said probe with said interrogating radiation generated by a suitable source, thereby generating luminescence radiation emitted by the probe;
(c) directing a fraction of the intensity of said luminescence radiation to photodetector means;
and
(d) measuring the decay time of said luminescence radiation, said decay time being an indicator of the probe temperature.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/010,585Filed 28 Jan 1993 · division
Priority: 6 Aug 1982
Granted: 26 Jul 1994
Term ends: Not estimatedThe source records don’t support an estimate.

Classification18 codes

G06F 3/041
Arrangements for converting the position or the displacement of a member into a coded form: digitisers, e.g. for touch screens or touch pads,…
G01D 5/35354
Using other arrangements than interferometer arrangements: sensor working in reflection
G01D 5/35377
Optical fibre sensor using a particular arrangement of the optical fibre itself: means for amplifying or modifying the measured quantity
G01J 1/58
Photometry, e.g. photographic exposure meter: using luminescence generated by light

Family

Serial405,732Parent of this continuation · filed 6 Aug 1982
Serial608,932Parent of this continuation-in-part · filed 14 May 1984
Serial711,062Parent of this division · filed 12 Mar 1985
Serial516,532Parent of this continuation-in-part · filed 30 Apr 1990
Serial812,050Parent of this division · filed 23 Dec 1991
US 5,222,810 AParent of this division
US 5,090,818 AParent of this continuation-in-part
US 5,004,913 AParent of this division
US 4,708,494 AParent of this continuation-in-part
US 5,332,316 AThis patent

From the US filing history. Foreign family members aren’t listed.