Optical temperature measurement technique utilizing phosphors
First Claim
1. For a temperature measuring system having a visible or near-visible electromagnetic radiation detector optically coupled to receive radiation indicative of temperature, a radiation emitting temperature sensor, comprising:
- a substrate adapted to be positioned in heat conductive relationship with an environment whose temperature is to be measured, said substrate being a length of optical fiber, anda quantity of phosphor material coated on one end of said optical fiber in a manner to be viewed by said optical coupling when said substrate is positioned in a heat conductive relationship with said environment, said phosphor being characterized by emitting, when excited, detectable optical radiation that varies as a known function of the phosphor temperature.
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Accused Products
Abstract
A technique of temperature measurement 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 emitted radiation being brought to a detector by an optical system that may include an optical fiber. Several specific applications of this technique are disclosed, such as temperature monitoring of electrical equipment and industrial processing, medical temperature instrumentation including the use of disposable elements that contain a small quantity of the temperature dependent phosphor, special and multiple probes, the use of liquid phosphors, and a phosphor paint for monitoring surface temperatures.
161 Citations
68 Claims
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1. For a temperature measuring system having a visible or near-visible electromagnetic radiation detector optically coupled to receive radiation indicative of temperature, a radiation emitting temperature sensor, comprising:
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a substrate adapted to be positioned in heat conductive relationship with an environment whose temperature is to be measured, said substrate being a length of optical fiber, and a quantity of phosphor material coated on one end of said optical fiber in a manner to be viewed by said optical coupling when said substrate is positioned in a heat conductive relationship with said environment, said phosphor being characterized by emitting, when excited, detectable optical radiation that varies as a known function of the phosphor temperature. - View Dependent Claims (2, 3, 4, 5)
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- 6. An optical temperature sensor comprising a length of optical fiber having a layer of phosphor material held at one end thereof in optical communication therewith, said phosphor being characterized by emitting, when excited, detectable optical radiation that varies as a known function of the phosphor temperature.
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9. An optical temperature sensor comprising a length of optical fiber having a layer of phosphor material held at one end thereof in optical communication therewith, said phosphor being characterized by emitting, when excited, detectable optical radiation that varies as a known function of the phosphor temperature, said optical fiber having only one optical communication channel between said phosphor and another end of said optical fiber.
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10. An optical temperature sensor, comprising:
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a length of a single optical fiber having first and second ends, and a layer of phosphor material attached at said first end in optical communication with said optical fiber, said phosphor being characterized by emitting, when excited by visible or near visible electromagnetic radiation, electromagnetic radiation within two wavelength bands that are substantially optically isolatable from each other and from said excitation radiation. - View Dependent Claims (11)
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- 12. A temperature sensing material adapted especially to be placed in heat conductive contact with an object whose temperature is to be optically determined, comprising a physical mixture of a substantially optically transparent vehicle and a phosphor, said phosphor being characterized by emitting, when excicted, electromagnetic radiation within optically isolatable bandwidths at at least two distinct wavelength ranges and with relative intensities therein that vary as a known function of the phosphor temperature, said phosphor additionally being characterized by including a physical mixture of at least two chemically different phosphors wherein the emitted radiation of one phosphor is within one of said two wavelength bands and that of the other phosphor is within the other of said two wavelength bands.
- 13. A temperature sensing material adapted especially to be placed in heat conductive contact with an object whose temperature is to be optically determined, comprising a physical mixture of a substantially optically transparent vehicle and a phosphor, said phosphor being characterized by emitting, when excited, electromagnetic radiation within optically isolatable bandwidths at at least two distinct wavelength ranges and with relative intensities therein that vary as a known function of the phosphor temperature, said phosphor additionally being characterized by comprising a common host compound in which two different activator elements are present wherein the emitted radiation within one of said at least two distinct wavelength ranges is the result of one activator and the other of said at least two distinct wavelength ranges if the result of the other activator.
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18. A temperature sensing material in fluid state and adapted especially to be placed in heat conductive contact with an object whose temperature is to be optically determined, comprising a physical mixture of a substantially optically transparent vehicle and a phosphor, said phosphor being characterized by emitting, when excited, electromagnetic radiation within optically isolatable bandwidths at at least two distinct wavelength ranges and with relative intensities therein that vary as a known function of the Phosphor temperature.
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19. A temperature sensing material adapted especially to be placed in heat conductive contact with an object whose temperature is to be optically determined, comprising a physical mixture of a substantially optically transparent vehicle and a phosphor, said phosphor being characterized by emitting, when excited, electromagnetic radiation within optically isolatable bandwidths at at least two distinct wavelength ranges and with relative intensities therein that vary as a known function of the phosphor temperature, said phosphor additionally including a rare earth in liquid solution with fluorescein.
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22. A method of determining the temperature of a plurality of locations with common signal processing, comprising the steps of:
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positioning a distinct layer of phosphor material at each of said plurality of locations, said phosphor being characterized by emitting, when excited, detectable optical radiation whose intensity varies as a known function of the phosphor temperature, exciting said phosphor at each of said locations to cause its said temperature dependent emission, optically directing said phosphor emission from each of said locations to a common detecting station, detecting at said common detecting station phosphor emission intensities from each of said locations, thereby to develop electrical signals proportional to the detected intensities from each location in time sequence, and electrically processing by common circuitry said time sequence electrical signals in a manner to obtain a signal from each location that is an indication of the temperature of the phosphor layer at that location. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. A method of determining the temperature of an object, comprising the steps of:
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positioning phosphor material in a heat transmittive relationship with said object, said phosphor being characterized by emitting, when excited, electromagnetic radiation within optically isolatable bandwidths at at least two distinct wavelength ranges and with relative intensities therein that vary as a known function of the phosphor temperature, said phosphor material including a physical mixture of at least two phosphor compounds wherein one of said at least two distinct wavelength ranges is caused by one compound and the other wavelength range by the other compound. exciting said phosphor to cause emission of said at least two wavelength bands, optically directing said phosphor emission to a detecting station, and detecting the relative intensities of said at least two distinct wavelength radiation bands, whereby said relative intensity is an indication of the temperature of the phosphor layer and related thereto by said known temperature emission function.
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34. A method of determining the temperature of an object, comprising the steps of:
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35. positioning phosphor material in a heat transmittive relationship with said object, said phosphor being characterized by emitting, when excited, electromagnetic radiation within optically isolatable bandwidths at at least two distinct wavelength ranges and with relative intensities therein that vary as a known function of the phosphor temperature, said phosphor material including a chemical compound having a single host with two distinct activator elements wherein one of said at least two wavelength ranges is caused by one activator and the other of said wavelength ranges is caused by the other activator,
exciting said phosphor to cause emission of said at least two wavelength bands, optically directing said phosphor emission to a detecting station, and detecting the relative intensities of said at least two distinct wavelength radiation bands, whereby said relative intensity is an indication of the temperature of the phosphor layer and related thereto by said known temperature emission function.
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36. A method of determining the temperature of an object, comprising the steps of:
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positioning liquid state phosphor material in a heat transmittive relationship with said object, said phosphor being characterized by emitting, when excited, electromagnetic radiation within optically isolatable bandwidths at at least two distinct wavelength ranges and with relative intensities therein that vary as a known function of the phosphor temperature, said phosphor material having two distinct activator elements wherein one of said at least two wavelength ranges is caused by one activator and the other of said wavelength ranges is caused by the other activator, exciting said phosphor to cause emission of said at least two wavelength bands, optically directing said phosphor emission to a detecting station, and detecting the relative intensities of said at least two distinct wavelength radiation bands, whereby said relative intensity is an indication of the temperature of the phosphor layer and related thereto by said known temperature emission function.
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37. A method of determining the temperature of an object comprising the steps of:
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positioning liquid state phosphor material in a heat transmittive relationship with said object, said phosphor being characterized by emitting, when excited, electromagnetic radiation within optically isolatable bandwidths at at least two distinct wavelength ranges and with relative intensities therein that vary as a known function of the phosphor temperature, said phosphor material having a single activator element wherein both of said at least two wavelength ranges are caused by said single activator, exciting said phosphor to cause emission of said at least two wavelength bands, optically directing said phosphor emission to a detecting station, and detecting the relative intensities of said at least two distinct wavelength radiation bands, whereby said relative intensity is an indication of the temperature of the phosphor layer and related thereto by said known temperature emission function.
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40. A method of determining the temperature of an object, comprising the steps of:
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providing a length of optical fiber, positioning over one end of the optical fiber a sleeve having a closed end, said closed end having a guantity of phosphor thereon, said phosphor being characterized by emitting, when excited, detectable optical radiation that varies as a known function of the phosphor temperature, placing said probe cover in a heat transmittive relationship with said object, exciting said phosphor to cause emission of said optical radiation, directing said phosphor emission through said optical fiber to a detecting station at another end of the optical fiber, and detecting at the detecting station the intensity of said optical radiation, whereby said intensity is an indication of the temperature of the phosphor layer and related thereto by said known temperature emission function.
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41. A system for determining the temperature of an object, comprising:
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a quantity of phosphor material held in a heat transmittive relationship with said object, said phosphor being characterized by emitting, when excited, electromagnetic radiation within optically isolatable bandwidths at at least two distinct wavelength ranges and with intensities therein that vary as a known function of the phosphor temperature, said phosphor material including a physical mixture of at least two phosphor chemical compounds wherein one of said at least two distinct wavelength ranges is caused by one compound and the other wavelength range by the other compound, means for exciting said phosphor material to cause emission of said at least two wavelength bands, means for independently detecting the intensity of radiation emitted by the phosphor material and each of said at least two wavelength bands, and means for comparing the detected intensities, whereby the temperature of said object can be remotely determined.
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42. A system for determining the temperature of an object, comprising:
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a quantity of phosphor material held in a heat transmittive relationship with said object, said phosphor being characterized by emitting, when excited, electromagnetic radiation within optically isolatable bandwidths at at least two distinct wavelength ranges and with intensities therein that vary as a known function of the phosphor temperature, said phosphor material including a chemical compound having a single host with two distinct activator elements wherein one of said at least two wavelength ranges is caused by one activator and the other of said wavelength ranges is caused by the other activator, means for exciting said phosphor material to cause emission of said at least two wavelength bands, means for independently detecting the intensity of radiation emitted by the phosphor material and each of said at least two wavelength bands, and means for comparing the detected intensities, whereby the temperature of said object can be remotely determined. - View Dependent Claims (44, 45, 47, 48, 49, 50)
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43. A system for determining the temperature of an object, comprising:
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a quantity of phosphor material in a liquid state positioned in a heat transmittive relationship with said object, said phosphor being characterized by emitting, when excited, electromagnetic radiation within optically isolatable bandwidths at at least two distinct wavelength ranges and with intensities therein that vary as a known function of the phosphor temperature, means for exciting said phosphor material to cause emission of said at least two wavelength bands, means for independently detecting the intensity of radiation emitted by the phosphor material and each of said at least two wavelength bands, and means for comparing the detected intensities, whereby the temperature of said object can be remotely determined.
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46. A system for measuring the temperature of a plurality of locations, comprising:
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means for providing phosphor excitation at each of said locations, whereby phosphor material may be positioned at each of said locations wherein the phosphor is characterized by emitting, when excited, electromagnetic radiation within substantially optically isolatable bandwidths at at least two defined wavelength ranges and with relative intensities therein that vary as a known function of the phosphor temperature, means removed from said locations for detecting intensity levels within said at least two wavelength bands emitted by any phosphor located at said locations, and electronic means receiving output signals from said detecting means for determining ratios of intensities within each of the two distinct wavelength ranges at each of said locations, whereby the ratio for each location is an indication of temperature of each location.
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51. An optical thermometer element, comprising:
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a length of optical fiber, means for emitting optical radiation of an input wavelength band along said optical fiber from one end thereof to the other, means optically coupled to said one end of the optical fiber for separately detecting the intensity of optical radiation within two separable output wavelength bands being passed along said optical fiber and generating an electrical signal proportional to each intensity, said two output wavelength bands being distinct from and nonoverlapping with said input wavelength band so that radiation within the input band has substantially no direct effect upon said electrical signals, means receiving said electrical signals for generating another signal proportional to the ratio of said radiation intensities within said two output wavelength bands, and means receiving said ratio electrical signal for indicating temperature. - View Dependent Claims (53)
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52. An optical temperature sensor, comprising:
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a length of an optical fiber terminating in an end, said optical fiber being constructed of a light transmitting core portion and surrounding cladding, said cladding being eliminated for a distance along said fiber from said end, a temperature sensitive phosphor material held at the end of the core material as part of a heat conducting, light shielding tip, and a hollow cylindrical sleeve surrounding said core along its strip length between said tip and said cladding without touching the core, thereby to leave a void space between said sleeve and said core, said sleeve being made of a material that can operate at temperatures other than those at which the said cladding could perform its intended function successfully. - View Dependent Claims (54, 56, 57, 58, 59, 60)
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55. An optical temperature sensor comprising a bundle of individual optical fibers held together, each with temperature sensitive phosphor material coated ends positioned at various distinct locations along the length of the bundle, whereby a temperature profile may be obtained along the sensor in the region adjacent it.
- 61. An optical temperature sensor, comprising a plurality of optical fibers held together in a bundle in the form of a temperature probe, and an independent optical temperature sensing element held in light communication with each of the plurality of optical fibers at a unique position along the length of said probe, whereby a temperature profile may be obtained along the length of the probe.
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62. A method of obtaining a termperature profile along a path within an environment, comprising the steps of:
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positioning a plurality of optical fibers in a bundle along said path, each fiber terminating at one end thereof at a unique position along said path and with an optical temperature sensing element attached thereto, and measuring at another end of each otpical fiber an optical temperature sensing characteristic of its said optical element, whereby a profile of temperature along said path within said environment is obtained.
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66. A method of obtaining temperature profiles within an environment, comprising:
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positioning a plurality of optical fibers in at least two bundles along each of at least two paths that substantially intersect each other at a finite angle therebetween within said environment, each fiber terminating at one end thereof at a unique position along its said path and with an optical temperature sensing element attached to said end, and measuring at said antoher end of each optical fiber an optical temperature sensing characteristic of its said optical element, whereby a two-dimensional profile of temperature within said environment is obtained.
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Specification