Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
  • G01J3/28—Investigating the spectrum
  • G01J3/2803—Investigating the spectrum using photoelectric array detector
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
  • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
  • G01N21/27—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands using photo-electric detection ; circuits for computing concentration
  • G01N21/274—Calibration, base line adjustment, drift correction

Definitions

• the invention relates to an integrated and compact device making it possible to carry out the qualitative and quantitative identification of one or a plurality of physico-chemical entities included in a fluid, and this instantaneously.
• the object of the invention is to provide a device capable of processing online and instantaneously information from multi-wavelength detectors, and in particular to provide, in addition to qualitative indications, also the concentration of certain chemical species pre- determined, and this, directly from a raw medium, that is to say free from any prior physical and or chemical treatment, and therefore, estimate the quality of a sample by comparing the information thus collected with that contained in a database, so as to constitute a compact and integrated expert system capable of being used on site.
• This integrated device for instantaneous qualitative and quantitative identification of one or a plurality of physico-chemical entities contained in or on a sample, and capable of restoring one or more emission, absorption or reflectance spectra under the excitation of an electromagnetic wave, is characterized in that it includes within a shielded box:
• a polychromator at which the emission, absorption or reflectance spectra or spectra of the analyzed sample is routed, and intended, in known manner, to decompose this or these spectra into a series of optical signals of discrete variation wavelength
• a device for detecting optical signals positioned on the optical path of the signals coming from the polychromator, and intended to transform said optical signals into analog signals
• a transformation circuit coupled to said detection member, and intended to transform said analog signals into digital signals
• a central unit integrating into an associated memory a plurality of typical spectra representative of known and predetermined entities, and intended to simultaneously analyze the digital spectra thus obtained, and to compare after decorrelation these spectra with the spectra stored in said memory, and to deduce from this comparison the nature and the concentration of the predetermined physico-chemical entity or entities in the sample.
• the invention consists in using as an information source the emission, absorption or reflection spectra of the medium or of a sample of the medium analyzed, and in decorrelating these spectra in order to determine the species present, responsible for color.
• This spectral analysis is carried out instantaneously and independently of any prior treatment at the level of the medium studied, so that a very rapid response can be obtained, and therefore using this device to any type of expert system.
• all of the constituents of this box being integrated within a shielded box, the analyzes carried out are free from any alteration inherent both in magnetic fields, in electric fields, and in external pressure variations.
• the invention consists in integrating, within the same device, in an otherwise compact form, different organs capable of analyzing a whole absorption or emission spectrum, and of determining the nature and the respective quantity of a certain number of predetermined entities contained in the analyzed sample.
• the result of this analysis obtained directly in the clear, causes the central unit to induce the automatic triggering of sensory signals or the activation of specific organs, motors, robots, ...
• this device it is thus possible to obtain an immediate online analysis, and therefore to induce according to this analysis the activation of any associated organ, within the framework of security, alert, etc.
• the circuit for detecting the optical signals from the polychromator is constituted by a photodiode array or by a charge transfer circuit (CCD type circuit), or by any other detector capable of delivering an analog or digital signal referring to a wave length.
• CCD type circuit charge transfer circuit
• the acquisition of the emission, absorption or reflection spectrum of the analyzed sample consists, if this sample is liquid, by a dosing tank comprising at least two parallel quartz walls, transparent to the excitation beam. electro-magnetic, these walls possibly being virtual and powered by fiber optic devices for example.
• the tank In the context of acquiring a spectrum of a gas sample, the tank is replaced by a multiple reflection tank, also transparent to the excitation beam.
• the device also includes an integrated electrical power generator, for example consisting of a plurality of photoelectric cells, positioned outside the housing, so as to make this device autonomous , thus promoting its use on site.
• an integrated electrical power generator for example consisting of a plurality of photoelectric cells, positioned outside the housing, so as to make this device autonomous , thus promoting its use on site.
• the device according to the invention and schematically represented in FIG. 1 basically comprises an enclosure or case (1), comprising an opening at the level of which is conveyed by means of a collimator (2) and a lens (3 ), the emission or absorption spectrum emitted by a liquid or gaseous sample.
• This box is shielded, so that the internal volume it delimits is insensitive both to magnetic and electric fields, as to variations in external pressures.
• it is also impervious to light, except through the opening that it presents, but also to liquids. In this way, this device can perfectly be used in a hostile atmosphere, in particular industrial or natural, which the devices known to date did not allow to obtain.
• This spectrum is routed by any known means, and in particular by means of an optical fiber or a plurality of optical fibers.
• the arrival of this spectrum at the level of the objective (3) of the collimator (2) has been represented by the arrow A.
• the electromagnetic wave supporting this spectrum is then reflected by a mirror (4) at the level of a polychromator (5), constituted for example by a plane field network, intended to diffract the electromagnetic waves which reach it in a plurality of monochromatic beams of wavelength as a function of the diffraction angle.
• a polychromator (5) constituted for example by a plane field network
• These different beams end up on a linear array of 512 photo ⁇ diodes (6), intended to transform the electromagnetic signal received into a analog signal, representative of the light intensity of said electromagnetic signal.
• the array of photodiodes (6) .. or any other equivalent device restores an analog spectrum, from a spectrum decomposed by the polychromator into a discrete sequence of wavelengths.
• the analog signals coming from sensors are converted into digital signals, by means of an analog converter / digital integrated into said sensor, and for example plugged into it.
• an analog converter / digital integrated into said sensor can be in the form of an electronic card, of very particularly compact dimensions.
• the bar is replaced by a charge transfer device (CCD), which in known manner, directly transforms electromagnetic signals into digital signals.
• CCD charge transfer device
• the digital signals thus obtained are then processed at a central processing unit (7), typically consisting of a plurality of electronic cards, always with the same aim of achieving optimal compactness of the device.
• This unit integrated in the enclosure (1) of the device, comprises an associated memory at the level of which is stored a plurality of spectra representative of predetermined physical or chemical entities.
• suitable software is loaded into this processing unit (7), and is intended to compare the spectrum from the charge transfer circuit or the array of photodiodes, to the different spectra stored in the associated memory. To do this, the absorbance measured for a determined wavelength is considered to be equal to the sum of the absorbances of the different chemical entities present in the sample, plus a contribution from the spectral background from the interference.
• An appropriate digital processing carried out at said processing unit (7) compares the absorbance values measured for said determined wavelength with that of a file contained in the associated memory integrating the absorbtivity values of the constituents to dose. This calculation leads to a precise value of the concentration of the constituent sought. The consistency between the measurement and the model is ensured by the use of multimodel systems, known per se, which adjust the measured and calculated values of the absorbance.
• connection method used namely direct connection
• both of the analog / digital converter unit and on the detector unit (6), as well as of the cards making up the micro-controller (7) on the Said converter member it is thus possible to accelerate the speed of analysis, and to get rid of any signal distortions inherent in the background noise, which interfere with the measurements.
• an exciting incident beam typically constituted by ultra-violet or laser radiation
• an in situ analysis can be carried out by means of a highly collimated laser beam, and this in the context of ambient air pollution controls, in particular in an industrial or urban environment.
• a first application of this device consists in operating an instant dosage of defined chemical species, such as in particular nitrates, phenol, hexavalent chromium, metals - such as iron, copper, manganese, lead, zinc, cadmium. - organic products, chlorides, borates, phosphates, ammonium, etc .... and this in a liquid sample.
• defined chemical species such as in particular nitrates, phenol, hexavalent chromium, metals - such as iron, copper, manganese, lead, zinc, cadmium.
• organic products chlorides, borates, phosphates, ammonium, etc .... and this in a liquid sample.
• the device according to the invention provides a biological quality index, the result of which is obtained directly, either in plain text at the screen (9) associated with said central unit, or in the form of signals. digital or analog, capable of activating the triggering of other sensory signals, light or sound for example, or even the activation of particular organs.
• the device is associated with an automatic control of industrial processes, in which the previous device is integrated into the circuits controlling the production of various products, in particular chemicals.
• optical measurements can also be supplemented by the addition by the user or collected by the internal computer of external data, such as in particular those coming from flow measurement sensors and physical or physico-chemical data such as pH, rH (Redox potential), temperature, conductivity, quantity of dissolved oxygen, turbidity, in order to constitute an automatic "toximeter", ie a device capable of automatically and instantaneously measuring the toxicity of a given environment and in particular water.
• an automatic "toximeter” ie a device capable of automatically and instantaneously measuring the toxicity of a given environment and in particular water.
• the device of the invention can be coupled to a control network produced from a series of sensors transmitting by telephone, radio waves or even by satellite the data collected on the control sites, so as to be able to follow permanently the quality of industrial production, or the quality of natural waters in a watershed, or even the degree of air pollution of an industrial site or an agglomeration.
• This application can also be used to determine the quality of the ambient air, especially in industrial premises.
• an alert station is produced, capable of activating any triggering of an audible or visual alert, when a certain threshold is exceeded or of inducing the activation of motor organs, in the case of In this case, the closing of valves, the stopping of pumps for the drinking water supply network, or the launching of pre-established alert programs.
• the color of the flame of a plasma torch varies according to the metals it encounters.
• the device of the invention it is possible to control the machining installation in real time.
• the color observed depends directly on the wavelengths of the corresponding absorption or emission spectra. In this area, the device can instantly analyze the plasma emission spectrum.
• the device of the invention can also be used as a laboratory spectrophotometer, in particular in the context of analyzes in high pressure liquid phase chromatography, but also during the measurement of reaction kinetics, in spectroscopy.
• this device can be used for the optical detection and identification of an entity and in particular in the context of identification and recognition of parts.
• These parts advantageously receive an identifier, consisting for example of a patch of a few square millimeters, of any shape, but the color of which is specific and defined by its wavelength.
• this patch has a typical and unique absorption and emission spectrum, due to the uniqueness of the multi-wavelength spectrum corresponding to the associated color.
• a color code can then be edited, and serves as an identifier.
• the application of a patch on the identified object can be avoided, the identifier being constituted by the object or the entity itself, insofar as the absorption spectrum or of emission linked to its color was previously carried out and listed.
• this patch can be glued or fixed by any appropriate means to the object to be recognized.
• this patch is uniformly covered with the color corresponding to a determined wavelength, in other words a pentome.
• the device according to the invention aims first of all to capture the emission or absorption spectrum of this pentome, and this by means of an optical reader, consisting for example of a pencil.
• the latter is equipped with a waveguide, typically made up of optical fibers, allowing, on the one hand, the lighting of the identifier by routing a polychromatic light beam from a source contained in said pencil, typically white light, and on the other hand, the transmission of waves reflected or transmitted by the identifier at a plane field network, intended, as already specified, to diffract the waves which reach it according to a plurality of monochromatic beams of wavelength as a function of the diffraction angle.
• This network is integrated into the detection and identification device described above in conjunction with FIG. 1.
• the microcomputer delivers a unique code or reference, strictly corresponding to the wavelengths of the color of the patch.
• This code or this reference can be restored in multiple ways, and for example in visual, graphic form on a screen, or simply in analog or digital form in order to be transmitted to other organs, or devices capable of performing operations. determined once this particular code reaches them. We observe in this way that to a defined set of wavelengths corresponds a unique code. This process can therefore be applied to numerous uses and in different fields, in particular to the direct measurement of the pH of a colored solution.
• the device of the invention makes it possible to have an intelligent optical scanner, insofar as it is capable of processing online and instantaneously the information coming from a multi-wavelength detector, capturing spectra electromagnetic emitted by all entities. It therefore constitutes the basis of an expert system, usable in a very large number of fields.

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• Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• General Physics & Mathematics (AREA)
• Life Sciences & Earth Sciences (AREA)
• Theoretical Computer Science (AREA)
• Health & Medical Sciences (AREA)
• Mathematical Physics (AREA)
• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• Engineering & Computer Science (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Investigating Or Analysing Materials By Optical Means (AREA)

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• 1993
  • 1993-04-27 FR FR9305204A patent/FR2704650B1/fr not_active Expired - Fee Related
• 1994
  • 1994-04-27 US US08/360,744 patent/US5528363A/en not_active Expired - Fee Related
  • 1994-04-27 WO PCT/FR1994/000478 patent/WO1994025837A1/fr not_active Application Discontinuation
  • 1994-04-27 EP EP94914451A patent/EP0647316A1/de not_active Ceased

Non-Patent Citations (1)

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