Abstract: One form of evaluation apparatus comprising a plurality of light sources vertically arranged by one side of a carrier line in width direction Y perpendicular to carrying direction X of the carrier line; and a light-receiving section arranged by an opposite side of the carrier line in the width direction Y perpendicular to the carrying direction X of the carrier line.

Abstract: A method and apparatus for measuring the concentration of a trace nitrogen dioxide contained in the atmosphere on a pptv level with excellent accuracy by a single-wavelength laser induced fluorescence method. The device comprises a laser light source unit, a light excitation unit, a light guide unit, an air passing unit for passing either the air to be measured or a reference air prepared by removing nitrogen dioxide from the air to be measured, a light sensor unit and a control unit. A single-wavelength laser beam is applied to the air to be measured and the reference air. The intensity of the light emitted from the air to be measured and the intensity of the light emitted from the reference air are measured, and the concentration of nitrogen dioxide is determined by using the difference between the two.

Abstract: A method determines an analyte concentration in a sample. The sample includes the analyte and a substance. The method includes providing absorption data of the sample. The method further includes providing reference absorption data of the substance. The method further includes calculating a substance contribution of the absorption data. The method further includes subtracting the substance contribution from the absorption data, thereby providing corrected absorption data substantially free of a contribution from the substance.

Abstract: The invention concerns high sensitivity light scattering detection and its application to evaporative light scattering detection in liquid chromatography. The exemplary embodiment includes a detection cell to accept particles suspended in a gas stream and permit a polarized light beam to pass through a trajectory of the particles and gas stream. A sample light detector is disposed to detect light scattered in the detection cell. A light trap accepts the polarized beam after it passes through the detection cell. The light trap includes an elongated housing through which the polarized beam passes, and light absorptive material within the elongated housing. An absorptive filter is aligned such that the angle of incidence of the light beam upon the filter approximates Brewster's angle and the electric field vector of the beam is aligned with the plane of incidence between the beam and the filter. Other embodiments of the invention provide increased light collection.

Abstract: A system and method are provided for detecting contaminants or defects on a reticle in-situ. The system and method provide a system that measures the optical transmission through clear areas on a reticle and determines whether the optical transmission of a reticle has been degraded by contaminants or other defects.

Abstract: The present invention relates to a device for accomplishing noise reduction in a photoacoustic gas detector using a sound damping element and/or a background or reference microphone where a preferably larger external volume that acts as a sound damping element (SDE) is coupled to a smaller volume through which the gas diffuses. The coupling is accomplished in such a way that the externally generated sound waves incident upon the photoacoustic detector are adequately attenuated by the larger volume SDE without adversely affecting diffusion of the gaseous species of interest through the smaller volume for measurement by the detector. Preferably this is accomplished by coupling the larger SDE volume to the smaller gas diffusion volume by a long and thin pressure channel.

Abstract: Methods for the preparation of inorganic nanoparticles capable of fluorescence, wherein the nanoparticles consist of a host material that comprises at least one dopant. The synthesis of the invention in organic solvents allows to gain a considerably higher yield compared to the prior art synthesis in water. All kinds of objects can advantageously be marked and reliably authenticated by using an automated method on the basis of a characteristic emission. Further, the size distribution of the prepared nanoparticles is nartower which renders a subsequent size-selected separation process superfluous.

Abstract: A method is disclosed for repairing an opaque defect on a mask substrate. After examining one or more opaque patterns in a predetermined area of the mask substrate, at least one opaque defect in the opaque patterns is identified based on a difference between its light reflection rate and a reference reflection rate. A residue height of the opaque defect is further determined based on its light transmission rate, and a repair formula such as an etching dosage is devised based on the determined residue height.

Abstract: The present invention is a disposable sensor for use with a device that quantifies analytes in a gaseous sample. It comprises (i) a sensing element, (ii) a means for interfacing the disposable sensor with a gas analysis device, and (iii) a housing. When used with a device that can quantify the concentration of an analyte in a gas sample, the present invention facilitates the use of exhaled breath analysis as a clinical tool.

Abstract: A gas detector device comprises at least a VCSEL source (34, 36) and at least a light sensor (54, 56) for detecting a light beam (50, 52) having passed through a sample chamber (48) containing a given gas to be detected. The sensor is a photodiode in a first embodiment and its detection signal is time derivated by an electronic derivator (64) and then provided to two lock-in amplifiers (84, 86) in order to generate a F-detection and a 2F-detection, F being the frequency of a wavelength modulation of the source, and thus to provide two corresponding measuring signals the division of which gives a precise value of the gas concentration. In a second embodiment, the source is a pyroelectric sensor which directly provides a detection signal proportional to the time derivate of the light beam incident on this sensor. In this last case, the electronic derivator is thus eliminated.

Abstract: A system and method employing optical disc drives for quantitative analysis of physical, chemical and biochemical parameters are provided. The system including a disc drive for supporting and rotating an optical disc including at least one sensor spot; a light source for directing light onto the sensor spot; at least one optical pickup for detecting light transmitted from the sensor spot, the transmitted light being indicative of a concentration of a compound; and an analog-to-digital converter for quantifying an intensity of the transmitted light. The method comprising the steps of preparing the optical disc with a plurality of sensor spots, the sensor spots being responsive to a compound; exposing the optical disc to a fluid; measuring intensity of transmitted light from at least one of the plurality of sensor spots; and correlating the measured intensity of transmitted light to an amount of compound exposed to the optical disc.

Abstract: A method and apparatus for evaluating the scattering properties of a transparency image comprises projecting radiation through the transparency image to form a transmitted beam of radiation; splitting the transmitted beam of radiation into at least two distinct beams of radiation, a first distinct beam and a second distinct beam; measuring a first amount of energy in the first distinct beam that corresponds to non-scattered light; measuring a second amount of energy in the second distinct beam that corresponds to scattered light; and comparing the first amount of energy to the second amount of energy to determine the proportion of the transmitted beam of radiation that is not scattered.

Abstract: One form of evaluation apparatus comprising a plurality of light sources vertically arranged by one side of a carrier line in width direction Y perpendicular to carrying direction X of the carrier line; and a light-receiving section arranged by an opposite side of the carrier line in the width direction Y perpendicular to the carrying direction X of the carrier line.

Abstract: A multispectral selective reflection Lidar system generates alternating pulses of at least two wavelengths and senses returns for determining the presence of a predetermined material absorbing and reradiating one wavelength as selective reflections, but not the other. A detector can readily determine the presence or absence or an absorbing and reradiating return. The system is for preferred use as an orbiter sensor about a planetary body, such as a Jupiter moon, for determining the presence of organic material and for the relay of information back to earth.

Abstract: A double path microdrop optical biometric system comprises a micro container, a corner cube array, a collimator, a beam splitting device, a light source selector, a detector and a signal comparator unit. It utilizes the beam to penetrate a specimen with specific coloring agent twice. Then, the shade of the beam can be detected so that a signal comparator unit can calculate the absorptance. The required volume of the specimen used in the system is small. The precision will be doubled by the double path design. Its entire optic-electronic system is simple and at low cost. By using the LEDs, it can avoid the use of filter and solve the over-heating problem. Plus, it can execute many bio-chemical tests.

Abstract: The present invention relates to a device for accomplishing noise reduction in a photoacoustic gas detector using a sound damping element and/or a background or reference microphone where a preferably larger external volume that acts as a sound damping element (SDE) is coupled to a smaller volume through which the gas diffuses. The coupling is accomplished in such a way that the externally generated sound waves incident upon the photoacoustic detector are adequately attenuated by the larger volume SDE without adversely affecting diffusion of the gaseous species of interest through the smaller volume for measurement by the detector. Preferably this is accomplished by coupling the larger SDE volume to the smaller gas diffusion volume by a long and thin pressure channel.

Abstract: Optical phase detection includes generating a first lightwave having a first polarization and a second lightwave having a polarization that is offset from the first polarization, and imposing a relative delay between the first and second lightwaves. The relative delay causes a frequency offset between the lightwaves as wavelength is tuned over a designated wavelength range. Directing the first and second lightwaves to a target provides a third lightwave and a fourth lightwave. A polarization component of the third lightwave and a polarization component of the fourth lightwave are detected to provide a detected signal at the frequency offset. The optical phase detection then includes extracting a phase difference, induced by the target, between the polarization components of the third and the fourth lightwaves.

Abstract: The invention relates to a method for detecting and processing the amplitude and phase of signal waves. A Modulated signal source generates the signal waves which are modified by transmission medium or by reflection and scattering by at least one object. The modified signal waves are received and demodulated using a modulation signal. The amplitude of the modulated signal waves and their phase relationship to the modulation signal are measured and evaluated. The demodulated signal wave is converted into an electrical charge or charge displacement in the receiving medium and is distributed in accordance with a modulation signal to at least two readout outputs and fed to an evaluation unit. The evaluation unit produces the sum and difference of the output signals thus applying the value of the intensity and the phase position of the signal wave that has been scattered, reflected or delayed by the object.

Abstract: Disclosed are photometric methods and devices for determining optical pathlength of liquid samples containing analytes dissolved or suspended in a solvent. The methods and devices rely on determining a relationship between the light absorption properties of the solvent and the optical pathlength of liquid samples containing the solvent. This relationship is used to establish the optical pathlength for samples containing an unknown concentration of analyte but having similar solvent composition. Further disclosed are methods and devices for determining the concentration of analyte in such samples where both the optical pathlength and the concentration of analyte are unknown. The methods and devices rely on separately determining, at different wavelengths of light, light absorption by the solvent and light absorption by the analyte. Light absorption by the analyte, together with the optical pathlength so determined, is used to calculate the concentration of the analyte.

Abstract: A wavelength variable light source apparatus includes a light source slot section for generating laser light and a main control section into which the light source slot section is inserted and which is connected to the light source slot section. The main control section optionally varies a wavelength and an output level of the laser light from the light source slot section. An optical connecting mechanism between the light source slot section and the main control section supplies the main control section with a part of laser light from the light source slot section.

Abstract: The present invention relates to methods and devices for in-situ measurement of reaction components of interest during manufacturing of polycarbonate by melt polymerization. The present invention describes irradiating a molten polymer sample with UV/visible light, and generating an absorbance profile correlated to Fries products as well as uncapped phenolic groups in the sample. The methods and apparatus of the invention are suitable for monitoring of Fries products in reactions ranging in size from small scale combinatorial formats to production scale reactors. Also included in methods of the invention are univariate and multivariate analysis for prediction of linear Fries, branched Fries and uncapped phenolic end-groups in unknowns.

Abstract: A laser absorption spectrometer for making measurements of absorption spectra which includes a wavelength sensor that can measure the average wavelength of pulses from a laser on a pulse-by-pulse basis and that can measure the internal wavelength variation of laser pulses. The laser absorption spectrometer can be used with pulsed lasers like the quantum cascade laser to perform sensitive measurements of the absorption spectra even when there is pulse-to-pulse variation of average wavelength and when there are internal changes in the wavelength of the pulses.

Abstract: A method of detecting an object located within a dynamic scattering media, includes i) directing a continuous coherent light wave of predetermined wavelength into the media; ii) detecting dynamically scattered light emerging from the media; iii) correlating the detected light photons in the time or frequency domain; iv) determining the presence of an object from analysis of differences between the correlation and a correlation which would arise from photons scattered by the media only; and v) determining the approximate position of the object within the media from the analysis of the correlation and knowledge of the mean transport path of the light wave of predetermined wavelength within the media.

Abstract: An extremely convenient apparatus for evaluating the inner quality of vegetables and fruits which is small and inexpensive, can be introduced easily even by small-scaled enterprisers, in which an installation place can be changed easily, and safety and promptness of the replacing work of light sources are fully taking into consideration is provided.

Abstract: A method for detecting and localizing a target tissue within the body in the presence of ambient light in which an optical contrast agent is administered and allowed to become functionally localized within a contrast-labeled target tissue to be diagnosed. A light source is optically coupled to a tissue region potentially containing the contrast-labeled target tissue. A gated light detector is optically coupled to the tissue region and arranged to detect light substantially enriched in target signal as compared to ambient light, where the target signal is light that has passed into the contrast-labeled tissue region and been modified by the contrast agent. A computer receives signals from the detector, and passes these signals to memory for accumulation and storage, and to then to image processing engine for determination of the localization and distribution of the contrast agent.

Abstract: A method of improving spatial resolution of a pump-probe terahertz (THz) imaging system for producing an image of an object. The method provides a chopped optical gating beam focused on a semiconductive layer that is either part of the object or a discrete layer placed over the object. The gating beam is focused on a gating pulse focal spot having a diameter effective to cause measurable modulation in transmission of a THz beam through the semiconductive layer when the gating pulse is on as compared to when the gating pulse is off, creating alternating modulated THz beams for detection and processing. Systems for performing the method in transmission and reflection modes are also described.

Abstract: A method and a device for determining the resistance of an optical material to radiation damage, wherein several sample volumes (1a, 1b; 1211-1233) within the optical material are simultaneously irradiated with test radiation having differing, measured or preset radiant-energy densities. The radiation employed for all sample volumes comes from a common radiation source (3; 13) and at least one parameter indicative of the resistances to radiation damage of the irradiated sample volumes is measured using measuring radiation. The measuring radiation also comes from the same radiation source that supplies the test radiation and the material's resistance to radiation damage is determined based on a functional relation between its radiation-damage-resistance parameter and the radiant-energy densities, wherein that functional relation is determined using the values of the radiation-damage-resistance parameters measured for the various sample volumes for the various radiant-energy densities employed.

Abstract: The invention concerns a method for the photometric analysis of test elements with a detection zone which is stable towards positioning tolerances of the detection zone comprising the following steps: activating the first light source to irradiate a first region of the detection zone and detecting the light reflected from the detection zone or transmitted through the detection zone in order to generate a first detection signal (50), activating the second light source to irradiate a second region of the detection zone which is displaced relative to the first region in the direction of the positioning tolerance and detecting the light reflected from the detection zone or transmitted through the detection zone in order to generate a second detection signal (60), comparing the first and the second detection signal and determining whether the first and/or the second detection signal has been obtained by illuminating an area situated completely on the detection zone.

Abstract: A method and apparatus for detection of a particular material, such as photoresist material, on a sample surface. A narrow beam of light is projected onto the sample surface and the fluoresced and/or reflected light intensity at a particular wavelength band is measured by a light detector. The light intensity is converted to a numerical value and transmitted electronically to a logic circuit which determines the proper disposition of the sample. The logic circuit controls a sample-handling robotic device which sequentially transfers samples to and from a stage for testing and subsequent disposition. The method is particularly useful for detecting photo-resist material on the surface of a semiconductor wafer.

Abstract: The invention comprises UV/visible spectroscopic analysis of polycarbonate composition. The method comprises determination of the concentration of Fries products, as either total Fries products or as separate determinations of linear and branched components. The method also allows for simultaneous determination of uncapped phenolic end-groups. Determinations may be performed at a single wavelength or over the entire absorption band. The method is suitable for measuring of Fries products in samples ranging in size from small scale combinatorial formats to production scale reactors. The method is independent of reaction variables such as polymer molecular weight, reactor type, and reaction temperature.

Abstract: A system for conducting optical tests on a plurality of optical modules includes a plurality of optical signal sources and optical signal degradation elements optically communicating with input switches. The input switches sources supply optical test signals to optical modules (units under test) plugged into a common shelf. Output optical switches supply the output signals to a range of optical test equipment. A controller utilizes a database of test recipes to supervise and control the optical signal sources, optical signal degradation elements, units under test, input switches, output switches, and test equipment to conduct a variety of optical tests on the modules. With this architecture it is possible to subject a variety of different optical modules to a variety of different optical tests.

Abstract: A semiconductor impurity concentration testing apparatus includes a terahertz pulse light source that irradiates terahertz pulse light on a semiconductor material, a light detector that detects transmitted pulse light having been transmitted through the semiconductor material, a measurement device that ascertains a spectral transmittance based upon a time-series waveform of the electric field intensity of the transmitted pulse light and an arithmetic operation unit that calculates an impurity concentration in the semiconductor material based upon the spectral transmittance. By adopting such a structure, it becomes possible to measure and test the impurity concentration over the entire semiconductor material in a simple manner and to reproduce an image of the impurity distribution.

Abstract: According to the present invention, an apparatus for determining various processes of wafer fabrication suitable for a plurality of various processes of wafer fabrication, having: a plurality of wafer cassettes, each having a distinct transparency, used in the various processes of wafer fabrication; a sensor-set, used to detect the distinct transparency of each of the wafer cassettes, and output a signal corresponding to the distinct transparency; and an amplifier, connected to the sensor-set to receive the signal, thus reading the distinct transparency, so as to determine the type of the wafer cassettes. Furthermore, a method for determining various processes of wafer fabrication includes the steps of: providing a plurality of wafer cassettes, each having a distinct transparency, used in the various processes of wafer fabrication; reading the distinct transparency of each of the wafer cassettes; and determining the type of the wafer cassettes according to the distinct transparency.

Abstract: Disclosed are photometric methods and devices for determining optical pathlength of liquid samples containing analytes dissolved or suspended in a solvent. The methods and devices rely on determining a relationship between the light absorption properties of the solvent and the optical pathlength of liquid samples containing the solvent. This relationship is used to establish the optical pathlength for samples containing an unknown concentration of analyte but having similar solvent composition. Further disclosed are methods and devices for determining the concentration of analyte in such samples where both the optical pathlength and the concentration of analyte are unknown. The methods and devices rely on separately determining, at different wavelengths of light, light absorption by the solvent and light absorption by the analyte. Light absorption by the analyte, together with the optical pathlength so determined, is used to calculate the concentration of the analyte.

Abstract: Described is a method for calibrating a spectrophometric apparatus and determining the concentration of an analyte in a sample. This method involves incorporating at least one primary calibration algorithm that uses an order of derivative of absorbance obtained for at least one of a standard set of wavelengths, on a second apparatus. The absorbance values of the sample are measured on the second apparatus at three or more wavelengths from a wavelength calibration table. Interpolated absorbance values are derived from the measured absorbance values for wavelengths from a standard set of wavelengths. A derivative of the interpolated absorbance values is obtained, using the same order of derivative used by the first apparatus. Followed by calculating a concentration of the Analyte in the sample, by applying the Primary Calibration Algorithm to the derivative.

Abstract: A method and device for fluorimetric determination of a biological, chemical or physical parameter of a sample utilize at least two different luminescent materials, the first of which is sensitive to the parameter, at least with respect to luminescence intensity, and the second of which is insensitive to the parameter, at least with respect to luminescence intensity and decay time. The luminescent materials have different decay times. The time- or phase behaviour of the resulting luminescence response is used to form a reference value for determination of a parameter.

Abstract: The present invention relates to an internal quality measuring apparatus for measuring an internal quality of an object, and the apparatus has a conveying device, a detecting device, a light projecting device, a light receiving device, an analyzing device and a pseudo-object member interposing device, and the analyzing device compares light received with a pseudo-object member, with reference data preliminarily stored, and correct a result of the analysis, based thereon.

Abstract: A reference wavelength light generating apparatus is disclosed in which light emitted from a light source is branched by a light branching unit, one of the branched lights is extracted as a measuring beam and the other is extracted as reference wavelength light by passing through a collimator and an absorbing member and then being reflected by a reflecting member to return to the branching unit.

Abstract: Disclosed are photometric methods and devices for determining optical pathlength of liquid samples containing analytes dissolved or suspended in a solvent. The methods and devices rely on determining a relationship between the light absorption properties of the solvent and the optical pathlength of liquid samples containing the solvent. This relationship is used to establish the optical pathlength for samples containing an unknown concentration of analyte but having similar solvent composition. Further disclosed are methods and devices for determining the concentration of analyte in such samples where both the optical pathlength and the concentration of analyte are unknown. The methods and devices rely on separately determining, at different wavelengths of light, light absorption by the solvent and light absorption by the analyte. Light absorption by the analyte, together with the optical pathlength so determined, is used to calculate the concentration of the analyte.

Abstract: The invention concerns a method and device for automatic cleaning of opto-electronic measuring systems used in process-technology for the analysis of substances in liquids and gases by means of optical absorption and fluorescence. The method is characterized in that the soiling degree is detected by the opto-electronic sensor system itself and, with predetermined soiling degree, a cleaning liquid cleans the soiling-sensitive optical components and detects the residual soiling, which is then evaluated quantitatively and compensated for in the signal analysis.

Abstract: An ozone detector in the form of two basic embodiments which can measure ozone concentration in ambient air at 0.001-1 ppm. The first embodiment includes a stretched elastic material and a standard which can give ozone concentration in response to degree of microcracking or frosting of the elastic material. The second embodiment includes a chamber containing a long strip of elastic material, a component for stretching the material, a light source for generating a light and illuminating the film and a detector for detecting reflected, transmitted through or scattered light by the material.

Abstract: A method of analysing powder formed as a mixture of pharmaceutical ingredients and derived from a bulk preparation of powder by spectrophotometric analysis utilising transmission measurements. A sample powder is removed from the bulk mixture and pressed into a test wafer and spectrophotometrically analysed for the transmitted beam to provide an assay test spectrum of actual absorption characteristics of ingredients in the material of the wafer. These characteristics of the assay test spectrum are compared with predetermined assay standard spectra determined from individual standard wafers for each relevant ingredient in the powder mixture by measuring absorption characteristics of the individual ingredients from the transmitted beam at known wavelengths of the beam to assess acceptability of the homogenity and distribution of the relevant ingredient in the powder of the sample. The wafer is preferably pressed with flat and parallel opposed end faces through which the beam is directed.

Abstract: Disclosed are photometric methods and devices for determining optical pathlength of liquid samples containing analytes dissolved or suspended in a solvent. The methods and devices rely on determining a relationship between the light absorption properties of the solvent and the optical pathlength of liquid samples containing the solvent. This relationship is used to establish the optical pathlength for samples containing an unknown concentration of analyte but having similar solvent composition. Further disclosed are methods and devices for determining the concentration of analyte in such samples where both the optical pathlength and the concentration of analyte are unknown. The methods and devices rely on separately determining, at different wavelengths of light, light absorption by the solvent and light absorption by the analyte. Light absorption by the analyte, together with the optical pathlength so determined, is used to calculate the concentration of the analyte.

Abstract: Post-manufacturing analysis of a semiconductor device is enhanced via a method that uses a light emitting diode (LED) formed in a semiconductor die. According to an example embodiment of the present invention, a LED is formed within a semiconductor die having a circuit side opposite a back side. The LED is activated and generates radiation. Substrate is removed from the device, and the amount of radiation that passes through the substrate is detected. The amount of radiation that passes through the die is a function of the absorption characteristics of the die and the substrate thickness. By detecting the radiation and using the absorption characteristics of the die, the amount of substrate remaining in the back side of the die is determined and the substrate removal process is controlled therefrom.

Abstract: The present invention relates to an internal quality measuring apparatus for measuring an internal quality of an object, and the apparatus has a conveying device, a detecting device, a light projecting device, a light receiving device, an analyzing device and a pseudo-object member interposing device, and the analyzing device compares light received with a pseudo-object member, with reference data preliminarily stored, and correct a result of the analysis, based thereon.

Abstract: A method whereby the average paper fiber area density (weight per unit area) can be directly calculated from the intensity of transmitted, scattered light at two different wavelengths, one being a non-absorpted wavelength. Also, the method makes it possible to derive the water percentage per fiber area density from a two-wavelength measurement. In the optical measuring technique optical transmitted intensity, for example, at 2.1 microns cellulose absorption line is measured and compared with another scattered, optical transmitted intensity reference in the nearby spectrum region, such as 1.68 microns, where there is no absorption. From the ratio of these two intensities, one can calculate the scattering absorption coefficient at 2.1 microns. This absorption coefficient at this wavelength is, then, experimentally correlated to the paper fiber area density. The water percentage per fiber area density can be derived from this two-wavelength measurement approach.

Abstract: In an inspecting method of a color filter, comprising irradiating light from a light source to a coloring portion, measuring a transmitting light amount transmitted through the coloring portion by a light receiving element, and calculating a coloring density of the coloring portion, the light amount of the light source is set substantially constant, the amount of incident light received by the light receiving element is adjusted by an optical element arranged within an optical path, the transmitting light amount of an uncoloring portion is measured and the coloring density of the coloring portion is inspected by comparing the transmitting light amount of the coloring portion to the transmitting light amount of the uncoloring portion.

Abstract: The present invention relates to an internal quality measuring apparatus for measuring an internal quality of an object, and the apparatus has a conveying device, a detecting device, a light projecting device, a light receiving device, an analyzing device and a pseudo-object member interposing device, and the analyzing device compares light received with a pseudo-object member, with reference data preliminarily stored, and correct a result of the analysis, based thereon.

Abstract: In a method of optically determining the total hemoglobin concentration (tHb) in non-hemolyzed whole blood, using at least two wavelengths for measuring, a first wavelength of .lambda.<805 nm and a second wavelength of .lambda.>805 nm is employed, such that the following is valid for the absorption coefficients of the hemoglobin derivatives O.sub.2 Hb and RHb at the two measurement wavelengths .lambda..sub.1 and .lambda..sub.2 : .sigma.O(.lambda..sub.1).about..sigma.R(.lambda..sub.2) and .sigma.R(.lambda..sub.1).about..sigma.O(.lambda..sub.2). The sum of absorption values A.sub.1 and A.sub.2 measured at wavelengths .lambda..sub.1 and .lambda..sub.2 will be a quantity which is proportional to the total hemoglobin concentration tHb and independent of the oxygen saturation O.sub.2sat.

Abstract: A measuring apparatus of absorption information of scattering medium, comprising a light source for generating pulsed light, a light incidence section for making the pulsed light incident to a scattering medium, a light receiving section for receiving the light having propagated inside the measured object, a signal detecting section for temporally cutting a portion out of a light signal obtained by the light receiving section to acquire a measurement signal corresponding to the cut-out signal, a first arithmetic section for performing a measurement for acquiring measurement signals respectively at plural different timings or the like and for deriving a time integration value and a mean optical pathlength for each of the plural measurement signals obtained, and a second arithmetic section for calculating a change amount of concentration of an absorptive constituent, based on a predetermined relation among plural time integration values, plural mean optical pathlengths, an absorption coefficient per unit concen