Luxtron Corporation

Other

Spectrotherm Corporation

Kenneth A Wickersheim

Mei H Sun

Stanley O Heinemann

Bruce E Adams

James H Kim

Stanley O Hinemann

A video camera of a type using an array of charge coupled devices (CCDs) is utilized to measure a condition, such as temperature, by imaging onto the camera a luminescent signal which contains information of the signal's decay time. The luminescent decay time is measured by comparing, such as by ratioing, the integrated signal values obtained in successive frames of operation of the CCD. One application includes use to measure a two-dimensional temperature distribution across a surface. The surface of interest is either coated with a layer of the luminescent material or emissions from the surface are imaged onto a separate luminescent screen. Another application is as a multiplexer and detector system for a large array of optical fiber sensors, a luminescent signal from each of the sensors being imaged through its respective fiber onto a unique one or more of CCD photosites.

Luminescent decay time measurements by use of a CCD camera

High temperature range black body techniques are combined with lower temperature range photoluminescent techniques to provide an optical method and apparatus for measuring temperature over a very wide range. Among the various optical probe configurations disclosed which combine the black body and photoluminescent technologies is an optical temperature measuring probe including an elongated transparent light pipe with a black body cavity and a photoluminescent material adjacent one end of the light pipe. Signal detection and processing can be combined, and temperature measurements made by the photoluminescent technique within an overlap of the two temperature ranges can be used to calibrate measurements made in the higher range by the black body technique.

Temperature measurement with combined photo-luminescent and black body

High temperature range black body techniques are combined with lower temperature range photoluminescent techniques to provide an optical method and apparatus for measuring temperature over a very wide range. Various optical probe configurations are disclosed which combine the black body and photoluminescent technologies. Signal detection and processing can be combined, and temperature measurements made by the photoluminescent technique within an overlap of the two temperature ranges can be used to calibrate measurements made in the higher range by the black body technique.

Fiberoptic sensors of various configurations are provided for measuring the magnitude of the electric or magnetic fields, and thereby the power, at local points within a relatively high-power electromagnetic heating environment such as occurs, for example, in a microwave oven or an industrial microwave processing chamber. Each type of sensor includes one element that is heated by either the oscillating electric or magnetic field, and an optical temperature measuring element positioned to be heated by the first element, its temperature being optically determined by an instrument to which an opposite end of the optical fiber length is connected.

Fiberoptic techniques for measuring the magnitude of local microwave

Method of making a fiberoptic sensor of a microwave field

Several specific types of optical sensors capable of measuring temperature, pressure, force, acceleration, radiation and electrical fields, fluid level, vapor pressure, and the like, are disclosed, along with an electro-optical system for detecting the optical signal developed by the sensor. One such probe utilizes a convex shaped structure consisting of an elastomeric material attached to an end of an optical fiber, the elastomeric material being coated with a luminescent material, a combination that is capable of measuring both temperature and pressure. Such a probe is also specifically adapted for measuring surface temperature by making a good physical contact with the surface being measured. Another such probe utilizes a similar structure but of a non-elastomeric material for the purpose of detecting both temperature and either index of refraction or vapor pressure changes. Improvements in other existing sensors of a wide variety of physical parameters other than temperature are also described wherein temperature is simultaneously measured for correcting such physical parameter measurements that are affected by temperature variations.

Fiberoptic sensing of temperature and/or other physical parameters

A single sensor is provided as part of a fiberoptic probe to measure up to three parameters, namely pressure (or force or displacement), temperature, and heat flow or fluid velocity. A solid elastomeric optical element is formed at the end of optical fiber transmission medium, and adjacent light reflective and temperature dependent materials are formed on the resulting convex surface of the optical element. The amount of light reflected is proportional to the force or pressure against the element. The temperature dependent material is preferably a luminescent material. Over the luminescent material is formed a layer of material that is absorptive of infrared radiation, thereby allowing a determination of characteristics of heat or fluid flow by measuring the rate at which heat is carried away from the infrared heated layer. The sensor can be formed at the end of a single optical fiber, thereby having extensive applications where a very small sensor is required. One such application is a medical or clinical one, where the sensor is mounted in a catheter for providing pressure, flow and temperature of the blood in a blood vessel.

Three-parameter optical fiber sensor and system

A technique of measuring very high temperatures by positioning a blackbody sensor in thermal communication with an environment or object whose temperature is to be measured, communicating infrared emissions having an energy level proportional to such temperature from the sensor to an infrared absorber positioned a distance away from the sensor where the ambient temperature is significantly reduced, and then optically measuring the temperature of the absorber by a technique that uses visible or near visible optical radiation, such as one using a luminescent sensor. The measured temperature of the absorber is proportional to that of the blackbody sensor.

Optical system using a luminescent material sensor for measuring very

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 luminescent 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.

Optical temperature measurement techniques

An optical fiber temperature sensing probe for implantation into a human body or other object that is being heated either by ultrasonic radiation alone or by a combination of ultrasonic and electromagnetic (radio frequency or microwave) energy. Several embodiments are described of probes adapted to measure temperature in an ultrasound field without errors being introduced by direct absorption of ultrasonic energy or by viscous heating, even when plastic fiber is utilized.

Optical fiber probe for measuring the temperature of an ultrasonically

Several specific types of optical sensors capable of measuring temperature, pressure, force, acceleration, radiation and electrical fields, fluid level, vapor pressure, and the like, are disclosed, along with an electro-optical system for detecting the optical signal developed by the sensor. One such probe utilizes a convex shaped structure consisting of an elastomeric material attached to an end of an optical fiber, the elastomeric material being coated with a luminescent material, a combination that is capable of measuring both temperature and pressure. Such a probe is also specifically adapted for measuring surface temperature by making a good physical contact with the surface being measured. Another such probe utilizes a similar structure but of a non-elastomeric material for the purpose of detecting both temperature and either index of refraction of vapor pressure changes. Improvements in other existing sensors of a wide variety of physical parameters other than temperature are also described wherein temperature is simultaneously measured for correcting such physical parameter measurements that are affected by temperature variations.

An optical fiber temperature sensing probe is implanted into a human body or other object that is being heated, either by ultrasonic radiation alone or by a combination of ultrasonic and electromagnetic (radio frequency or microwave) energy. In order to measure temperature in an ultrasound field without the probe introducing errors, the probe is made to be substantially thermally non-conducting, made of materials that do not absorb compressional energy, and has a small diameter relative to the length of the ultrasonic heating waves.

Technique for optically measuring the temperature of an ultrasonically

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.

Growing community of inventors

Menlo Park, CA, United States of America

Kenneth A Wickersheim