Thermal measuring and testing – Temperature measurement – Nonelectrical – nonmagnetic – or nonmechanical temperature...
Reexamination Certificate
2001-09-07
2003-11-18
Fulton, Christopher W. (Department: 2859)
Thermal measuring and testing
Temperature measurement
Nonelectrical, nonmagnetic, or nonmechanical temperature...
C374S137000, C250S461100
Reexamination Certificate
active
06648506
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable.
Reference to a “Computer Listing Appendix Submitted on a Compact Disc”
Not Applicable.
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to a fluorescent imaging thermographic method and system for use particularly in surface temperature measurements, which are reproducible over time. The invention provides a temperature-sensitive fluorescent probe comprising a rare earth compound in an ultraviolet and fluorescence transparent medium wherein the intensity of fluorescence varies as the temperature varies, in particular, probes comprising Europium(1,1,1,5,5,5-hexafluoroacetylacetone)
3
for measuring temperatures greater than 24° C., Terbium(1,1,1,5,5,5-hexafluoroacetylacetone)
3
for measuring temperatures less than 24° C., or both. The probe is applied as a layer to a surface, exposed to fluorescence-inducing energy, and the emitted fluorescence is captured as an image by a CCD camera. A novel ratio imaging algorithm enables the temperature at each location on the surface to be determined.
(2) Description of Related Art
The prior art has developed methods using fluorescence measurements to determine the temperature of a surface. The problem has been that the measurements have not been reproducible over time because of the photo-bleaching of the fluorescent probe.
U.S. Pat. No. 2,551,650 to Urbach discloses the measurement of temperature distributions on the surface of solid bodies using fluorescence emitting phosphors.
U.S. Pat. Nos. 4,075,493, 4,215,275, 4,448,547, and 4,560,286 to Wickersheim discloses a technique wherein an object or environment to be measured is provided with a phosphor material layer that emits at least two optically isolatable wavelength ranges whose intensity ratio depends upon the object or environment temperature. The technique uses optical system filters and signal processing to determine the temperature profile of the surface of the object. In particular embodiments, the emitted radiation is brought to the detector by an optical system, which may include an optical fiber.
U.S. Pat. No. 4,302,970 to Snitzer et al. discloses a temperature probe formed by an optical fiber having a core fabricated from a glass host doped with a trivalent rare earth such as europium positioned at the location where temperature is to be measured.
U.S. Pat. No. 4,374,037 to Takahashi discloses a method for preparing a divalent-europium-activated calcium sulfide phosphor comprising reacting a molten mixture consisting essentially of alkaline-earth-metal chloride and europium chloride with gaseous carbon disulfide at temperatures between 850° C. and 1200° C. for one to six hours.
U.S. Pat. No. 4,455,741 to Kolochner discloses a solid state electronic device that is optically monitored during fabrication to detect hot spots which are indicative of faulty operation. The surface temperature of the device is measured by applying a fluorescent material to the device and subsequently monitoring the temperature dependent fluorescence of the material.
U.S. Pat. No. 4,523,799 to Delhaye et al. discloses a device that optimizes the coupling of two optical systems for the observation and analysis of objects, one of the systems producing the illumination of a point on the object being studied while the other produces the image of that point in an analyzer.
U.S. Pat. Nos. 4,652,143 and 4,789,992 to Wickersheim et al. discloses an optical temperature measurement technique that utilizes the decaying luminescent intensity characteristic of a sensor composed of a luminescent material that is excited to luminescence by a light pulse or other periodic or other intermittent source of radiation. The luminescence emissions of a preferred sensor exhibit an approximately exponential decay with time that is the average of a distribution of chemically reproducible crystallites and are repeatable with a high degree of accuracy regardless of excitation level or prior temperature history of the sensor.
U.S. Pat. No. 4,708,494 to Kleinerman discloses methods and materials associated with remote optical measurements of temperatures with luminescent sensors.
U.S. Pat. No. 4,819,658 to Kolodner discloses a method and apparatus for measuring the temperature profile of a surface exhibiting spacial or temporal variations in temperature. The fluorescent material is applied in a layer less than 10 &mgr;m in thickness and in thermal contact with the surface.
U.S. Pat. No. 5,149,972 to Fay et al. discloses an imaging apparatus, which includes a fluorescence imaging microscope, ultraviolet radiation source capable of producing a plurality of ultraviolet excitation wavelengths, a filter device to select a first and a second excitation wavelength from the plurality of ultraviolet excitation wavelengths, a sample chamber to hold a sample for illumination by the radiation of the first and second wavelengths, and a processor in communication with a photometer to record the intensity signal produced by the photometer.
U.S. Pat. No. 5,304,809 to Wickersheim discloses the use of a CCD camera to measure the image and luminescent signal from a fluorescent layer disposed on an object. The system further contains a computer for measuring the differences in transmissions and calculating the temperature of the object.
U.S. Pat. No. 5,435,937 to Bell et al. discloses a polymer material containing compounds, which are internally luminescent.
U.S. Pat. No. 5,618,732 to Pease et al. discloses a method of calibrating photo-activatable chemiluminescent matrices.
U.S. Pat. No. 5,705,821 to Barton et al. discloses a scanning fluorescence microthermal imaging apparatus and method. The apparatus focuses a laser onto a thin fluorescent film disposed over the surface of an integrated circuit. By collecting fluorescent radiation information from the film, and performing point-by-point data collection with a single-point photodetector, a thermal map of the integrated circuit is formed to measure any localized heating associated with defects in the integrated circuit.
U.S. Pat. No. 6,123,455 to Beshears et al. discloses an apparatus for measuring the temperature of a moving substrate which includes an air gun to spray controlled amounts of a powdered phosphor onto the moving substrate. A laser produces light pulses, and optics direct the light pulses onto the phosphor on the moving substrate, in response to which the phosphor emits luminescence with a decay rate indicative of the temperature of the phosphor. A photodetector detects the luminescence.
Crofcheck et al. (J. Polymer Sci: Part A: Polymer Chem. 33: 1735-1744 (1995)) discloses a method for monitoring the temperature of high speed cationic photopolymerizations using temperature-sensitive tris(&bgr;-diketone) chelates of europium probes and detecting temperature-sensitive luminescence of the probes during the reaction. The method uses either europium(1,1,1,5,5,5-hexafluoroacetylacetone)
3
or europium(benzoyl-1,1,1-trifluoroacetone)
3
as the probe and measures the temperature of the photopolymerizations using a two-wavelength ratiometric method.
SUMMARY OF THE INVENTION
The present invention provides a fluorescent imaging thermographic method and system for use particularly in surface temperature measurements, which are reproducible over time. The invention provides a temperature-sensitive fluorescent probe comprising a rare earth compound in an ultraviolet and fluorescence transparent medium wherein the intensity of fluorescence varies as the temperature varies, in particular, provided are probes comprising Europium(1,1,1,5,5,5-hexafluoroacetylacetone)
3
for measuring temperatures greater than 20° C. or Terbium(1,1,1,5,5,5-hexafluoroacetylacetone)
3
for measuring temperatures less than 20° C., or both. The probe is applied as a layer to a surface, exposed to fluorescence-inducing energy, and the emitted fluorescence is captured as an image by a CCD camera. A novel ratio imaging algorithm enables the temperature at each location on the surface to be determined.
Therefor
Lian Bin
McGrath John J.
Fulton Christopher W.
Jagan Mirellys
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