Abstract: Techniques for measuring the temperature at various locations through the thickness of glass products and to control the glass processing operation with the sensed temperature information are disclosed. Fluorescence emission of iron or cerium in glass is excited and imaged onto segmented detectors. Spatially resolved temperature data are obtained through correlation of the detected photoluminescence signal with location within the glass. In one form the detected photoluminescence is compared to detected scattered excitation light to determine temperature. Stress information is obtained from the time history of the temperature profile data and used to evaluate the quality of processed glass. A heating or cooling rate of the glass is also controlled to maintain a predetermined desired temperature profile in the glass.

Abstract: An optical waveguide path coupling structure is realized without requiring highly accurate alignment.

Abstract: A process and an apparatus preferably used during the photocagulation of the fundus of human eyes or animals measures density fluctuations caused by pulsed irradiation, such as a laser irradiation source, on a material. A wherein a measuring signal is acoustically or optically detected. The change of the intensity and/or of the time slope of the measuring signal resulting from the irradiation of a specific material point is detected. A linear thermo-elastic signal fraction is removed from the measuring signal.

Abstract: A method and apparatus for maintaining a viewing window of a detector substantially clean includes enclosing the detector within a housing, and moving a target surface relative to the viewing window to create an airflow adjacent the viewing window. The housing can include an aperture through which the viewing window of the sensor views the target surface. Motion of the target surface creates an airflow velocity adjacent the viewing window for maintaining the viewing window substantially clean. To increase the accuracy of the detector, a high emissivity area is provided on an outside surface of the housing which faces the target surface.

Abstract: A method of detecting a temperature of an object in a multiple-reflection environment by a radiation pyrometer includes the steps of detecting a radiation strength emitted from a target region of an object, applying a correction to the radiation strength so as to correct the effect of multiple reflections of a radiation emitted from the object, applying a correction to the radiation strength so as to correct a reflection loss caused at an end surface of an optical medium interposed between the object and a sensing head of the pyrometer, applying a correction to the radiation strength with regard to an optical absorption loss caused in the optical medium, and applying a correction to the radiation strength with regard to a stray radiation coming in to the sensing head from a source other than the target region of the object.

Abstract: A method is provided wherein a temperature reading error of a pyrometer is avoided. An upper pyrometer is used to detect infrared radiation from a test layer formed on a test substrate under standard processing conditions. The infrared radiation from the test layer has a period having a length which is indicative of growth rate of the layer. The period is generally inversely proportional to the growth rate. The growth rate is directly related to the temperature.

Abstract: A method for determining oxidation in turbine buckets allows for conditional based maintenance of the turbine buckets. The method includes measuring a temperature of a turbine bucket and comparing the measured temperature to a temperature of a reference turbine bucket to determine the condition of the bucket. The method provides useful temperature data to determine if the turbine should be stopped and the bucket serviced. This method may be used in place of interval based maintenance to increase bucket life, reduce bucket failure, and increase turbine operating time.

Abstract: A sensor is provided that includes at least one functional coating layer that includes a UV-absorbing polymer. Methods for making the inventive sensors are also provided.

Abstract: A method for determining the temperature of a surface upon which a coating is grown using optical pyrometry by correcting Kirchhoff's law for errors in the emissivity or reflectance measurements associated with the growth of the coating and subsequent changes in the surface thermal emission and heat transfer characteristics. By a calibration process that can be carried out in situ in the chamber where the coating process occurs, an error calibration parameter can be determined that allows more precise determination of the temperature of the surface using optical pyrometry systems. The calibration process needs only to be carried out when the physical characteristics of the coating chamber change.

Abstract: A method and system for calibrating radiation sensing devices, such as pyrometers, in thermal processing chambers are disclosed. The system includes a reflective device positioned opposite the radiation sensing devices and a calibrating light source which emits light energy onto the reflective device. The system is designed so that each radiation sensing device is exposed to the same intensity of light being reflected off the reflective device, which has a preset value. The radiation sensing devices are then used to measure the amount of light energy being reflected which is then compared to the preset value for making any necessary adjustments.

Abstract: A technique and system for tuning temperature sensor readings in a thermal processing chamber includes determining an actual temperature profile for a substrate based on measurements of the substrate. A simulated temperature profile for the substrate is calculated using a respective interim temperature correction value for one or more temperature sensors associated with the chamber. A Gaussian-like distribution for thermal contributions from multiple radiation sources in the chamber can be used to simulate the temperature profile. The simulated temperature profile and the actual temperature profile are combined to form an estimated temperature profile. A final value for each respective temperature correction value is determined using an optimization algorithm which results in the estimated temperature profile being substantially uniform across the surface of the substrate.

Abstract: A liquid cooled light pipe is disclosed which allows effective pyrometric temperature measurements using a remote detector. Temperature of the light pipe assembly is controlled and maintained at an approximately constant value in order to establish good long-term temperature measurement accuracy. The temperature-controlled light pipe assembly of this invention can be used for multi-point temperature measurements of a heated body with good spatial resolution for real-time multi-zone temperature control applications.

Abstract: This invention describes method and apparatus for protecting optical sensors in harsh industrial environments, particularly welding and machining. In a preferred embodiment, a sacrificial window is utilized which is replaced as needed. Numerous design features of such windows are disclosed. Other embodiments include protective baffles and other features.

Abstract: An ultra violet light sterilizing apparatus utilizing a silicon carbide (SiC) photodiode sensor is described. The ultraviolet light fluid sterilization apparatus includes a fluid chamber, at least one ultraviolet light source configured to emit ultraviolet light into the fluid chamber, and at least one ultraviolet light sensor that includes a silicon carbide photodiode. Each UV light sensor includes a sealed outer housing having an optically transparent window. A silicon carbide photodiode is located inside the housing adjacent the transparent window. Each UV light sensor also includes a signal amplification unit that includes an amplifier mounted on a printed circuit board located inside the housing. The UV sterilization apparatus also includes a controller configured to receive, as input, a signal from each ultraviolet light sensor.

Abstract: There is shown an arrangement for detecting elastic deformation of a tool shaft carried by a machine tool and, in turn, carrying a cutting bit. An optical fibre section is mounted in or on the shaft at a distance from its neutral bending line in the longitudinal direction of said shaft. The optical fibre section, which follows the elastic deformation of the shaft, extends parallel with and at a constant distance fro the neutral bending axis of said shaft, so that elongation of the fibre section forms a measurement of bending of the shaft in an axial plane that includes the optical fibre section. The optical fibre section has at least two longitudinally spaced partial reflection means and means are connected to the optical fibre section to determine interferometrically a change in distance between the partial reflection means in the optical fibre section, wherein the change in distance forms a measurement of shaft curvature between the two partial reflection means.

Abstract: A method of true temperature determination, including, (a) acquiring radiation emitted by an object at a plurality of wavelengths (50), (b) determining a characteristic of the acquired radiation which is based on a relationship between radiative emissions acquired at more than one wavelength (50), (c) determining a factor related to an error, using the characteristic (54) and calculating a current temperature of the object based on the correctional factor (56). Preferably, the factor is a vector of values indicating at least one emissivity value.

Abstract: An method and an apparatus for measuring the partial pressure of gases dissolved in liquids in plants for carrying out biotechnological and food technological processes includes a measuring space which is separated by a gas-permeable diaphragm which is permeable for the gas to be determined. A light emission source produces a light ray with a wavelength which is absorbed by the gas to be determined. The light ray is directed into the measuring space. A measuring device is provided for determining the light ray leaving the measuring space. The measuring space, the light emission and the measuring device are arranged in a rod-shaped probe. The probe is capable of being sterilized. The measuring space is filled with a fluid which does not chemically react with the gas to be determined.

Abstract: A method for calibrating an optical pyrometer to an external reference point. By changing the focus of the optical pyrometer without physically moving the pyrometer, calibration of the optical pyrometer can be accomplished without modifying the semiconductor operation. Broadly speaking, the present invention contemplates an apparatus for calibrating an optical pyrometer. The apparatus includes a first optical source in a heating chamber with an optical port, an optical pyrometer, a mirror, and a second optical source. The optical pyrometer is positioned to receive light rays from a first optical source residing inside the heating chamber. The second optical source is located external to the heating chamber. The second optical source serves as an external reference point. The external location of the second optical source allows for calibration of the optical pyrometer without modification of the heating chamber or the first optical source residing inside the heating chamber.

Abstract: A method and an apparatus for monitoring simultaneously the temperature and velocity of a thermal spray jet. The apparatus has a sensor head directed at the jet, the sensor head having two optical fibers carrying radiation from the jet to a remote detection unit which comprises two or three photodetectors. The radiation carried by the separate optical fibers is filtered at two different wavelengths before being passed to the photodetectors. The temperature of the jet is determined by analyzing the ratio of the energy radiated at the two wavelengths. The velocity of the jet is determined, knowing the distance between the fibers, by measuring the time delay between the signals carried by the separate fibers using cross-correlation.

Abstract: An optical pyrometer and method of use provides a dual path optical system for processing light from a radiating stationary object or a moving thermal stream. Light is collected by primary optics forming an intermediate image in a plane of a field limiting aperture for establishing a preferred field of view. The light is then split into a pair of complimentary beams with one beam directed through a long wavelength filter and the other directed through a short wavelength filter. Both beams then move through separate secondary optics and are then rejoined and directed as normal non-overlapping and adjacent images onto a digitizing detector for capturing the images. Signals from the detector are handled by a computer where a ratio mapping of pair of signals from corresponding points on the two images is constructed and displayed on a monitor for viewing a temperature map of the object or thermal stream.

Abstract: The temperature of an infrared radiation scattering medium which contains water, for example, biological tissue and paper, cement and clay substrates, is determined by exposing the medium to infrared radiation, measuring the reflected radiation scattered by the medium, comparing the reflected radiation with calibrated values, and evaluating the temperature of the medium from the comparison; the technique provides a means of non-invasive determination of temperature in biological tissue which has utility in medical diagnosis.

Abstract: This invention describes a method and apparatus for protecting optical sensors in harsh industrial environments, particularly welding and machining. In a preferred embodiment, a sacrificial window is utilized which is replaced as needed. Numerous design features of such windows are disclosed. Other embodiments include protective baffles and other features.

Abstract: Method and apparatus for the optical determination of the temperature of a gaseous mixture, the method comprising the stages consisting:of exciting in the infrared range the molecules of a gas of said mixture, from a first vibrational level towards a second vibrational level;of allowing the rotational relaxation of said molecules between the different rotational sub-levels of said second vibrational level;of measuring the ratio of the populations of molecules located at two of said rotational sub-levels; andof deducing from said ratio the temperature of the gaseous mixture.

Abstract: The invention provides an apparatus, and method of making the apparatus, for optical sensing of parameters in high temperature environments, such as chemical reaction zones, combustion zones, high temperature drying processes, and the like. Moreover, the optical apparatus of the invention are able to operate in high temperature environments without need for associated cooling equipment. The optical elements of the sensors are fabricated from a material that is refractory, is transparent to electromagnetic radiation, has low thermal conductivity, and that reduces in viscosity when heated to a temperature well above the operating temperature to which it will be subjected in the monitoring environment. Preferably, the optical elements, and even mechanical elements, are made of a vitreous silica material.

Abstract: The disclosure describes a high-temperature optical transducer capable of acquiring input variables for closed-loop control of combustion systems. The key components of the innovation are a high-temperature, embedded photodiode, the use of low-cost, integral absorption filters; and the use of an embedded high-temperature preamplifier circuit. These components are combined in an optical-to-electrical signal transducer deployed in the high-temperature combustion environment, thus avoiding the high costs of optical signal transmission. The optical signals to the transducer are employed to recognize events in real-time such as the ignition spark, the start of combustion, end of combustion, misfires, and knocking. The outputs from the transducer may be used in a statistical fashion to control engine roughness and cyclic stability. By resolving specific colors in the flame, the optical sensors may also be used to determine the temperature and the emission production in the combustion chamber.

Abstract: A radiation thermometer comprises an optical objective through which radiation to be detected passes. A beam splitter has a central region through which a central portion of the radiation which has passed through the objective passes undeflected and an outer region which reflects radiation surrounding the central portion. An eye piece receives radiation passing through the beam splitter; and a radiation detector receives radiation reflected by the beam splitter.

Abstract: An optical sensor system includes a housing having an open end; first and second windows situated in the housing; a fastener for situating the first window closer to the open end than the second window and permitting an air exchange between a sensing region and the second window; a hermetic seal between the second window and the housing; and an optical sensor situated between the second window and a wall of the housing such that the air exchange does not occur inside the optical sensor. The first and second windows can include materials selected from the group consisting of sapphire, quartz, and glass; the optical sensor to be protected can include silicon carbide; and the sensing region can include a combustion region.

Abstract: A method of calibrating an optical pyrometer comprising placing an oven, a wafer with a reference region on at least part of one of its faces, the reference region having an electromagnetic wave reflection discontinuity at a known temperature value, transmitting an electromagnetic wave in the direction of the reference region, measuring and recording the intensity of the wave reflected by the reference region, measuring and recording the temperature of the reference region by means of the optical pyrometer to be calibrated, increasing the temperature of the oven, determining the moment when a discontinuity in the reflection of the electromagnetic wave is observed, registering the temperature value measured by the pyrometer at this moment, comparing this measured temperature value with the known temperature value, and causing the temperature value measured by the pyrometer and the known temperature value to coincide.

Abstract: A light emitting device for projecting a light beam onto a monitor area, and a light receiving device, arranged so that a light beam is not directly received by the device, for receiving diffused light caused as a result of fine particles, such as dust, or smoke caused by a fire, entering the monitor area, are provided. Also, an amplifying device for amplifying an output from the light receiving device, and a counting device for counting the output from the amplifying device in units of time are provided. In addition, a computing device for computing an average value or an integrated value of the output from the amplifying device in units of time, and a determining device for determining the level of contamination of the monitor area on the basis of the count value of the counting device and for determining the level of the fire on the basis of the average value or the integrated value computed by the computing device, are provided.

Abstract: An interferometric temperature sensing system provides a simplified design for accurately processing an interference fringe pattern using self coupling effects of a laser detection element, where a laser diode and an optical detection element are combined in one package. Accordingly, the present invention is easily made and the measurement of temperatures within a wide range can be easily performed.

Abstract: A radiation pyrometer for measuring the true temperature of a body is provided by detecting and measuring thermal radiation from the body based on the principle that the effects of angular emission I.sub.1 and reflection I.sub.2 on the polarization states p and s of radiation are complementary such that upon detecting the combined partial polarization state componentsI.sub.p =I.sub.1p +I.sub.2pI.sub.s =I.sub.1s +I.sub.2sand adjusting the intensity of the variable radiation source of the reflected radiation I.sub.2 until the combined partial radiation components I.sub.p and I.sub.s are equal, the effects of emissivity as well as diffusivity of the surface of the body are eliminated, thus obviating the need for any post processing of brightness temperature data.

Abstract: Apparatus for producing signal frequency shifts by stimulated Brillouin scattering comprises a pair of optical fibres (112,113) or a single high birefringence fibre which are illuminated by a laser beam to generate two back-scattered signals by stimulated Brillouin scattering and a mixer (117) to combine the two back-scattered signals to produce a beat frequency from the combined signals.

Abstract: An optical interferometer comprises a multi-mode sapphire fiber as a high temperature sensor. One end of the sapphire fiber is coupled to a silica fiber and, in turn, to the sapphire fiber. The sapphire fiber sensor produces reference and sensor reflections that produce optical fringes at the output of a detector coupled to the silica optical fiber via an opto-coupler. The optical fringes are related to displacements of the sensor which, in turn, can provide an indirect measurement of pressure, strain or temperature of the surface.

Abstract: A method is disclosed for continuously measuring the temperature of a semiconductor substrate in a chamber is disclosed. The first step of the method involves providing a substantially clean semiconductor substrate having a layer a reflective surface thereon into a chamber. A film is formed superjacent the surface by introducing a gas comprising at least one of N.sub.2, NH.sub.3, O.sub.2, N.sub.2 O, Ar, Ar--H.sub.2, H.sub.2, GeH.sub.4, or any fluorine based gas and photon energy in situ. The photon energy, having a wavelength substantially in the absorption band of silicon, generates a temperature substantially within the range of 500.degree. C. to 1250.degree. C. Subsequently, the reflectivity of the surface is measured prior to introducing the gas, and continuously, while forming the film until the film is substantially formed. The substrate is exposed to photon energy having a power level responsive to the measured reflectivities of the film.

Abstract: An apparatus for heat treating the surface of a body includes an infrared heat source carried on a stand. A circuit controls the energization of the lamp. The circuit includes a heat detector for detecting a targeted area temperature. The apparatus includes a sighting mechanism to permit an operator to accurately sight the heat detector against the surface to be heat treated.

Abstract: A light measurement device includes a photoelectric converter for receiving light from an object to be measured and converting the light to a measuring electrical energy in accordance with the intensity of the light, an offset amount measurement device for measuring the offset amount of the photoelectric converter, temperature measurement device for measuring a first temperature of the photoelectric converter when measuring the offset amount, and a second temperature of the photoelectric converter when measuring the light from the object, a memory device for storing a characteristic of the photoelectric converter with respect to temperature, correction amount calculation device for calculating a correction amount based on the characteristic, the first temperature, and the second temperature, and a light intensity calculation device for calculating a light intensity based on the measuring electrical energy, the offset amount, and the correction amount.

Abstract: A method and apparatus for measuring temperature by subjecting, to the temperature to be measured, a light-transmissive body of a material whose dimensions change in response to temperature, directing first rays of light from a light source through a first path including a predetermined distance of travel through the light-transmissive body, simultaneously directing second rays of light from the light source through a second path, parallel to the first path and of a linear length equal to that of the first path, but not including the predetermined distance of travel through the light transmissive body, and measuring the change in phases between the first and second light rays at the ends of the first and second paths, to thereby provide a measurement of the temperature to which the light-transmissive body was subjected.

Abstract: A non-contact pyrometric technique is provided for measuring the temperature and/or emissivity of an object that is being heated by electromagnetic radiation within the optical range. The measurement is made at short wavelengths for the best results. The measurement may be made at wavelengths within those of the heating optical radiation, and the resulting potential error from detecting heating radiation reflected from the object is avoided by one of two specific techniques. A first technique utilizes a mirror positioned between the heating lamps and the object, the mirror reflecting a narrow wavelength band of radiation in which the optical pyrometer detector operates. The second technique is to independently measure the a.c. ripple of the heating lamp radiation and subtract the background optical noise from the detected object signal in order to determine temperature and emissivity of the object. Both of these techniques can be combined, if desired.

Abstract: A method and apparatus to produce correction-free pyrometry is described. The method determines the optimum position for a pyrometer that "views" a specular, spherical or near-spherical target in a furnace through pyrometer optics and a window in a wall of the furnace. The positioning method uses nonparaxial optical analysis to determine the position of an image of the window in the target. The window image is free of any image of the furnace walls, that is, it is free from wall radiance, and pure target radiance can be obtained in that region. The optical analysis is then used to back project the pyrometer detector through the pyrometer optics and onto the surface of the target. If the detector projection falls completely within the image of the window, the detector will read only pure target radiance and no correction will be necessary to obtain the temperature of the target through pyrometry.

Abstract: A concentration correcting apparatus comprising a correction coefficient calculating means and a correcting means is shown and described. The correction coefficient calculating means calculates a correction coefficient for correcting the concentration of the material when the actual density of the medium at the measurement of the material is calculated in terms of the density of the medium under the reference temperature and pressure, from the results of the temperature measuring means and the pressure measuring means. The correcting means corrects the results of the material measuring means to a concentration under the reference temperature and pressure on the basis of the correction coefficient.

Abstract: A method and an apparatus are provided for calibrating a spectrometer, in particular a Fourier transform spectrometer (FTS), in particular for the infrared spectral range. At least four black body radiators of different temperatures are provided, which are arranged horizontally, i.e. parallel to the surface of the earth, thereby avoiding temperature gradients due to convection. The temperature of the at least four radiators is determined by means of the calibrating method without a separate measurement. In the method according to the invention, at the same time the absorption of the atmosphere is considered as a characteristic of the spectrometer, thereby eliminating separate measurement and correction thereof. In addition, for Fourier transform spectrometers the calibration is carried out by means of complex spectra.

Abstract: Thermal, optical, physical and chemical characteristics of a substrate (11) surface are determined with non-contact optical techniques that include illuminating (23) the surface with radiation having a ripple intensity characteristic (51), and then measuring the combined intensities (53) of that radiation after modification by the substrate surface and radiation emitted from the surface. Precise determinations of emissivity, reflectivity, temperature, changing surface composition, the existence of any layer formed on the surface and its thickness are all possible from this measurement. They may be made in situ and substantially in real time, thus allowing the measurement to control (39, 41) various processes of treating a substrate surface. This has significant applicability to semiconductor wafer processing and metal processing.

Abstract: A method for monitoring temperature in a turbine component includes detecting a change in photoconduction properties in a fiber-optical cable disposed inside a turbine component, being caused by a temperature change in the turbine component. An apparatus for monitoring temperature in a turbine component includes a fiber-optical cable disposed in the interior of a turbine component, and a device for detecting a change in photoconduction properties in the fiber-optical cable being caused by a temperature change in the turbine component.

Abstract: Apparatus for measuring the value of the directional spectral hemispherical reflectance of the surface of a target when not engaging but being spaced from the target employs a hollow elongated member having a longitudinal axis and first and second opposite ends. The area of the first end is relatively large relative to that of the second end. The first end is open. The member has an inner chamber extending between the ends and has an inner surface adapted to reflect light falling within a specified wave band. The member when the apparatus is in use is positioned with the first end adjacent but spaced from a selected portion of the surface of the target. The longitudinal axis is oriented essentially normal to a region on the selected surface which would be engaged by a line coincident with the axis and sufficiently extended outwardly from the first end.

Abstract: A high temperature optical probe for an optical gas temperature sensor includes a support, a generally conical hollow tip, and a joint physically interconnecting the support and the tip. The tip includes as an electromagnetic radiation emitter a sapphire-free ceramic selected from the group consisting of silicon carbide and silicon nitride.

Abstract: Method and apparatus for measuring the radiation originating from one side of a wafer of semiconductor material using a pyrometer, wherein non-blackbody compensation radiation is projected onto that side to compensate for the reflectivity of the wafer of material and wherein the intensity of the non-blackbody compensation radiation is controlled subject to the amount of radiation measured by the pyrometer.

Abstract: A method and apparatus is used to determine the thickness of a layer deposited on a specimen. For example, the thickness of a layer of polycrystalline may be measured as it is deposited over silicon oxide on a silicon wafer. The intensity of radiation emission at the top of the silicon wafer is detected. The temperature of the silicon wafer is measured and the variation in the intensity of radiation emission due to variation of the temperature is subtracted from the intensity of radiation emission detected at the top of the silicon wafer. The resultant signal is used to calculate the thickness of the polycrystalline silicon layer.

Abstract: A multi-point non-invasive, real-time pyrometry-based temperature sensor (200) for simultaneously sensing semiconductor wafer (22) temperature and compensating for wafer emissivity effects. The pyrometer (200) measures the radiant energy that a heated semiconductor wafer (22) emits and coherent beams of light (224) that the semiconductor wafer (22) reflects. As a result, the sensor (200) generates accurate, high-resolution multi-point measurements of semiconductor wafer (22) temperature during a device fabrication process. The pyrometer (200) includes an infrared laser source (202) that directs coherent light beam (203) into beam splitter (204). From the beam splitter (204), the coherent light beam (203) is split into numerous incident coherent beams (210). Beams (210) travel via optical fiber bundles (218) to the surface of semiconductor wafer (22) within the fabrication reactor (80). Each optical fiber bundle (218) collects reflected coherent light beam and radiant energy from wafer (22).

Abstract: An interferonmetric temperature measurement system is described for determining the temperature of a sample. The system comprises three detectors for measuring various intensities of a beam of electromagnetic radiation reflected off the sample and circuitry for determining the temperature from the intensities. The detectors measure the intensity of the beam and two orthogonally polarized components of the beam.

Abstract: A method is disclosed for continuously measuring the temperature of a semiconductor substrate in a chamber is disclosed. The first step of the method involves providing a substantially clean semiconductor substrate having a layer a reflective surface thereon into a chamber. A film is formed superjacent the surface by introducing a gas comprising at least one of N.sub.2, NH.sub.3, O.sub.2, N.sub.2 O, Ar, Ar--H.sub.2, H.sub.2, GeH.sub.4, or any fluorine based gas and photon energy in situ. The photon energy, having a wavelength substantially in the absorption band of silicon, generates a temperature substantially within the range of 500.degree. C. to 1250.degree. C. Subsequently, the reflectivity of the surface is measured prior to introducing the gas, and continuously, while forming the film until the film is substantially formed. The substrate is exposed to photon energy having a power level responsive to the measured reflectivities of the film.