EP1955033A2 - Systeme de detection integre portatif pour mesures spectrales - Google Patents

Systeme de detection integre portatif pour mesures spectrales

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Publication number
EP1955033A2
EP1955033A2 EP06838711A EP06838711A EP1955033A2 EP 1955033 A2 EP1955033 A2 EP 1955033A2 EP 06838711 A EP06838711 A EP 06838711A EP 06838711 A EP06838711 A EP 06838711A EP 1955033 A2 EP1955033 A2 EP 1955033A2
Authority
EP
European Patent Office
Prior art keywords
sample
spectral
measurement
data
detector
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP06838711A
Other languages
German (de)
English (en)
Other versions
EP1955033A4 (fr
Inventor
John Coates
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Microptix Technologies LLC
Original Assignee
Microptix Technologies LLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Microptix Technologies LLC filed Critical Microptix Technologies LLC
Publication of EP1955033A2 publication Critical patent/EP1955033A2/fr
Publication of EP1955033A4 publication Critical patent/EP1955033A4/fr
Withdrawn legal-status Critical Current

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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
    • G01J3/02—Details
    • 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
    • G01J3/02—Details
    • G01J3/0256—Compact construction
    • 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
    • G01J3/02—Details
    • G01J3/0264—Electrical interface; User interface
    • 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
    • G01J3/02—Details
    • G01J3/0272—Handheld
    • 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
    • G01J3/02—Details
    • G01J3/0291—Housings; Spectrometer accessories; Spatial arrangement of elements, e.g. folded path arrangements
    • 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
    • G01J3/12—Generating the spectrum; Monochromators
    • G01J3/26—Generating the spectrum; Monochromators using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters
    • 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
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/8483—Investigating reagent band
    • 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
    • G01J3/12—Generating the spectrum; Monochromators
    • G01J2003/1213—Filters in general, e.g. dichroic, band
    • 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
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • 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
    • G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
    • G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
    • G01N21/64—Fluorescence; Phosphorescence

Definitions

  • the present invention relates to a miniaturized integrated spectral sensor, with integrated sensed signal conditioning, signal exchange, and integration into a handheld device for the measurement of solution and solvent-based chemistries.
  • the device can be configured for solids or gases, but liquids are the preferred implementation.
  • the sensed information is converted into meaningful information in the form of concentrations of specified species and for the composition or properties of mixtures and composite materials.
  • spectrometers In a traditional laboratory, instruments described as spectrometers, spectrophotometers or photometers (referred to from here on as spectrometers) are used to make measurements on liquids or solutions containing one or more chemical substances. Such methods of analysis are used to measure the concentration of a component either directly or following the reaction with one or more chemical substances, usually described as reagents. In such reactions the analyte, or material being measured, is converted into a chemical form that can be detected within the spectral region covered by the instrument.
  • Examples can include the formation of a specific color, or the formation of a material that provides a characteristic fluorescence or luminescence, especially in the presence of radiation of specific wavelengths, such as an ultraviolet source, or the formation of a light scattering medium, where the degree of light scatter is proportional to the concentration of the analyte (substance or species being measured).
  • This latter case includes turbidity for the measurement of suspended materials.
  • spectral regions such as the ultraviolet, near infrared and the mid infrared, materials can have natural absorption characteristics, where the material can be measured directly in the absence of a reagent. Similar situations occur where an analyte is naturally colored or naturally fluorescent. In these situations reagents are not required.
  • the sample is normally placed in a separate container, such as a laboratory flask or bottle, prior to placement within the cell. Such a preparation can also require heating or an incubation period.
  • the cell is placed at a sampling point within the spectrometer. Typically, this sampling point is a chamber or sampling compartment, which is often light-tight, and can be sealed from interference from ambient light.
  • the sampling chamber may be configured to accept one or more sampling cells.
  • the sample cell may be configured for sample flow through the cell. In such systems, a reagent may be introduced in the sample flow, enabling the regent to interact with the sample in situ.
  • the present invention uses a miniaturized, low cost spectral sensing device, a major advancement in measurement opportunity over the status quo, and overcomes issues related to size or space occupied in the laboratory, or the size of a portable spectrometer.
  • Each device is intended to provide the functionality of a normal spectrometer or spectral analyzer, but at reduced cost, and with a significantly reduced size for the total package.
  • the spectral sensing component of the present invention is based on existing optical sensing technology constructed in accordance with the principles set forth in commonly- owned U.S. Patent Application Serial No. 10/913,819 filed Aug. 6, 2004 (now United States Patent No. 7,057,156), incorporated herein by reference, in its entirety.
  • the spectral sensing systems described feature specially assembled detection devices that incorporated the spectral selection elements required to generate the spectroscopic data for subsequent analysis.
  • One set of examples are linear variable filter (LVF) systems based on a silicon photodiode array that can offer spectral ranges of 360 nm to 700 nm (visible) and 600 nm to 1100 nm (short wave near Infrared (NIR)).
  • This also includes multi-element detectors that feature filter mosaics or filter arrays, such as multi-element color sensing devices.
  • the current implementations feature the spectral selection devices, nominally in the form of interference filters (LVF or otherwise) that are produced as an integrated component as part of the detector array fabrication, either by the array manufacturer or by a company specializing in thin film deposition.
  • the current invention includes full integration of the sample handling with the spectral sensing, and the spectral measurement electronics. The sample interface, the light source for the spectral measurement, the spectral detection system, the primary signal acquisition electronics, and the signal processing and display of the final analytical results are provided within a single package.
  • the package includes a sample transport mechanism whereby the sample, in liquid form, is drawn into the measurement area by an integrated pumping or suction device.
  • Said pump is either mechanically actuated by a spring or suction mechanism or electrically actuated by a suitable micro pump.
  • the sample area is integrated within a disposable sampler, and can be similar in concept to disposable pipettes or to the disposable tips used for micro- pipette systems.
  • the samplers denoted as Smart TipsTM or Smart SamplersTM, the reagents are included in an immobilized form.
  • the sampler is constructed to provide mixing of the reagents either prior to entry into the measurement zone, or within the measurement zone, thereby eliminating the need for external handling or mixing of reagents.
  • An option is included to make these Smart devices identifiable to the measurement system either by mechanical (keyed) or electronic means.
  • the spectral sensing systems can take a form similar in size and construction to a single-channel micro-pipette or a general purpose dispensing system, and can be battery powered.
  • the systems can include hardwired communications to a PC, laptop or handheld PDA via standard interfaces, such as USB, and can have the option for wireless communications via one of more of the standard protocols such as BlueTooth, ZigBee, IEEE 802.1 lb/g or equivalent standards.
  • the term integrated is used to indicate that the device is to be fabricated as a single structure, where the components are intimately interconnected in a miniaturized platform.
  • the system includes a sampling component, a spectral engine including a light or energy source and a sensing component and a signal conditioner, a signal exchange system, and a controller, all assembled as a single inter-connected structure.
  • the interfacing optics form part of the structure, with no requirement for additional imaging elements such as lenses or mirrors, as used in spectrometers, and as such is differentiated from traditional instruments and spectrometers.
  • the system can be configured to measure light/energy absorption or light/energy emission (as in fluorescence or luminescence).
  • the sampling component is in the form of a separable chamber with tip and optional sample transport mechanism (alternative designs can feature a separated pumping device), which can be made of a suitable material, such as a common plastic, that renders the part disposable.
  • the sampling component interfaces intimately with the spectral engine that includes an optical sensing system for nonintrusive detection of the spectral or optical characteristics of the sampled medium (normally a fluid).
  • the spectral engine further includes a light or energy source, spectral sensing component, featuring a fully integrated spectrally selective detection device (described as a spectrometer or a photometer on a chip), for measuring the characteristic chemical or physical features of the sample medium, an interface for a removable sample cell or chamber that is intimately connected to the source and sensing element, and is dimensionally optimized and matched to these components, and a microprocessor for conditioning the signals output from the spectral sensing element. Additional functions of the microprocessor include spectral data extraction, and the calculation of chemical composition or properties, method and calibration storage, and data communications.
  • the signal exchange system may be a wired or a wireless signal transfer device coupled locally or remotely to the sensor.
  • the primary power for the electronics is provided nominally via batteries, which can be of the rechargeable variety if required. However, the option to use tethered power, such as via a USB cable is included.
  • the spectral sensing device includes an integrated sample transport system to provide a means to introduce the sample fluid into the measurement region.
  • this sample transport is provided via a simple squeeze bulb, suction bellows or spring-driven piston pump, as implemented in commercial micro-pipettes.
  • a piston device or another form of pump, such as a piezo-driven micro-pump features an electronically controlled drive mechanism. Swept sample volumes can be small, being of the order of a few hundred microliters to a few milliliters (dependent on pathlength), at the most, and so the pumping capacity can be correspondingly low.
  • the fluid is drawn into the measurement region of the sensing device, as noted, via an integrated pump or suction device.
  • the measurement region is a removable component, defined as a sampler, and is implemented in the form of a modified pipette-like structure, where the fluid is drawn in through a tip.
  • the sampler measurement chamber includes reflective elements encapsulated and/or retained within the construction. These reflective elements capture the light/energy emerging from the source mounted within the optical interface of the spectral engine. This light/energy is then returned, in a retro-reflective manner back to the spectral sensing element (detector), which is also mounted within the optical interface of the spectral engine.
  • the light/energy passes through the fluid ⁇ ft at least three times; twice to and from the spectral engine and once between the two reflective elements.
  • This is equivalent to a single pass through a conventional liquid cell.
  • These dimensions can be set to be equivalent to normal pathlengths used in conventional cells, and these will be nominally from 1.0 mm to 10.0 cm (total distance). It is expected that in the standard format, this measurement chamber will be constructed from an optically transparent medium, and for most applications, this will be a clear plastic material. The latter is to be constructed as a molded part in the most common implementation of the device.
  • the total sampler construction can be produced in two or more parts, with the inner measurement area being encased within a black and/or optically opaque external shell. In the common implementation this can be made as a co- extruded part, or as an assembly made from two or more separate molded parts. Note that the optically opaque exterior of the sampler will make a positive light seal with the outer casing of the main measurement system. In this manner, the measurement area is shielded from external light sources, thereby ensuring accurate photometry, and also enabling low-light measurements, such as fluorescence and luminescence.
  • the fluid being measured will already contain an active chromophore (light absorbing entity related to the analyte) or fluorophore (light emitting entity related to the analyte).
  • This chromophore/fluorophore will either be native to the material being measured or induced by the use of one or more specific reagents.
  • the mixing of reagents to form a measurable solution is a standard practice in most testing laboratories, and it is also a standard procedure for most field-based testing.
  • the micro- spectral sensing system described in this package has the advantage that the swept volume required for the fluid by the measurement system is in the region of a few hundred microliters to a few milliliters.
  • Smart TipsTM or Smart SamplersTM are used. Smart Tips/Samplers are designed to enable reagent interaction and mixing to be carried out in situ, without the need for external reagents or mixing vessels.
  • the internal architecture of the tip or sampler includes molded features that generate turbulences when the fluid is drawn into the tip.
  • reagent or reagents to fulfill the requirement of the analysis can be located in an immobilized form (encapsulated in a water/solvent soluble • solid medium or a hydrophilic medium) adjacent to the entrance of the tip.
  • the medium and the reagent can dissolve in the sample or interact with the sample as it enters the tip or sampler, and the consequent solution can be agitated during its passage into the measurement region.
  • An option in the design is to key the fitting of the tip to the body of the measurement system in a way that the specific analysis can be automatically defined within the measurement device. This can be accomplished either by a physical key, or via electronic means, such as a bar code, a digital bar code, or by a technology such as RFID. In the case of the digital bar coding, this can be implemented by the use of an additional, well-defined chromophore/fluorophore (non- interfering) mixed in with the reagent.
  • the spectral measurement device is primarily intended for use with fluids.
  • optional tips/samplers and optional optical interface layouts will be considered for measurements of solids and gases.
  • These optional tips/samplers may be simple adaptations of the existing tips/samplers, such as the combination of an embedded chromophore located within the optical path, where this chromophore interacts with a reactive component in a gas or vapor.
  • the analyses can be made by direct contact with the surface material based on a diffuse reflectance or interactance method of measurement.
  • the calibration can be carried out within a controlled environment, and with a live connection to a PC or laptop computer for data logging and storage.
  • the calibration set can then be handled by an established procedure, such as a Beer-Lambert based calculation of light/energy absorption versus concentration relationship.
  • the coefficient(s) and intercept can be downloaded into the measurement system along with measurement settings and criteria.
  • Complex applications can require multivariate modeling, and in such cases the modeling equations can be downloaded.
  • the architecture of the onboard microprocessor can be sufficiently flexible to accommodate such downloads, and can accommodate multiple models/calibrations, dependent on the size of the calibration data, and the available onboard memory storage. This enables an end-user to customize the measurement system for a broad range of applications.
  • the system is not limited by design to fixed analyses.
  • the method of uploading (results) and downloading (methods and calibrations) can be enabled via either direct physical coupling to a PC, laptop computer or handheld PDA, or via a wireless connection.
  • Options for direct coupling can be via a standard serial interface, such as a USB port, or via some other standardized interface such as Ethernet or Firewire.
  • the wireless connection can be optional, and can be implemented on board the main electronics in a standardized format, such as BlueTooth, ZigBee, or a standard IEEE 802.1 lb/g or IEEE 802.14b.
  • the device can be provided with a user-configurable IP address.
  • one option for communication with the device can be from a web server, which will provide the option for remote access for upload and download.
  • FIG. 1 is a cross section of an example embodiment of a spectral sensing engine: integrated source, sample interface, spectral analyzer and detector.
  • FIGS. 2A, 2B and 2C are example combinations of optical filters and detector components used for spectral sensing.
  • FIG. 3 illustrates example electronic components for the integrated spectral sensor.
  • FIG. 4 illustrates example embodiments of the spectral sensing components - electronics.
  • FIG. 5 illustrates an example embodiment of the spectral engine component - sample integration.
  • FIG. 6 illustrates example embodiments of the spectral engine with sample interface tips.
  • FIG. 7 illustrates an example embodiment of the spectral engine with the sampler and its sample chamber and bellows.
  • FIG. 8 illustrates example embodiments of the spectral engine alternatives for solid sampling.
  • FIG. 9 illustrates an example embodiment of a Smart TipTM located on the spectral engine.
  • FIG. 10 illustrates an alternative embodiment showing the Smart SamplerTM with immobilized reagents in the tip or the sample housing.
  • FIG. 11 illustrates an example embodiment for a pipette-style design for spectral sensor.
  • FIG. 12 illustrates an example embodiment for a handheld design for the spectral sensor.
  • FIG. 13 illustrates an example embodiment of alternative design for an insertion spectral sensor.
  • FIG. 14 illustrates an example spectral sensor response in the visible region: colored dye solutions.
  • FIG. 15 illustrates an example spectral sensor response in the near infrared region spectra of common chemicals.
  • the present invention is an integrated handheld measurement system for spectral sensing of aqueous and organic solutions, certain gases and vapors, and for certain solid substrates, such as powders and extended solid surfaces.
  • the sensing aspect of this invention preferably includes one or more miniaturized optical spectral sensors located within the body of the handheld device.
  • FIG. 1 provides a symbolic representation of an example spectral sensing system, comprising a light or energy source 10, an optimized and integrated sample chamber 11, a spectral analyzer or spectrally selective element 12, and an integrated detection system 13.
  • Example embodiments of such spectral sensing systems are illustrated in FIGS 4 to 10.
  • the source is indicated as an incandescent-style of source, such as a tungsten source.
  • the invention covers various types of sources, such as solid-state sources (LEDs and diode lasers), MEMs-based thermal sources and gas discharge devices, where the source is optimized for the application and the spectral range of the overall spectral measurement system.
  • the optical layout shown in FIG 1 represents an energy/light transmission (or absorption) style of measurement.
  • the technology enables light scattering and optical emission measurements, such as fluorescence, phosphorescence, and luminescence, and can also be configured for reflectance and transflectance (transmission- reflection) measurements from surfaces. The latter is indicated as an example embodiment in FIG 8.
  • the individual spectral sensors are intended to be small and convenient to use, and can be optionally fabricated as low cost devices. As such, multiple implementations of the handheld devices can exist in the work place, or even in the home.
  • An optional component of the system is a wireless communications interface, based on a standard wireless platform, and conforming to published standards such as the IEEE 802.1 lb/g, ZigBee and Bluetooth.
  • the system design includes the wireless components located on the main electronics board(s) as shown, for example, in FIGS 4 and 5.
  • the objective of the wireless components is to provide an easy mechanism to download results from the spectral measurement device, and to upload new calibrations and measurement schemes.
  • An important component of the spectral sensor technology can be broadly described as an optical spectrometer on a chip as represented in FIG 2 by 14, 15 and 16. While optical sensors have been available, the present invention integrates an optical filter assembly 12 with a light or energy sensitive array 13 (FIG 1).
  • the optical filter technology used is either in the form of a continuous linear variable filter (LVF) 14, 15, or a filter array (patterned filter or mosaic) 16.
  • LVF linear variable filter
  • the resultant device or spectral sensing component 14, 15 is the most versatile and can be utilized for many applications, and for different spectral ranges, dependent on the detector array technology used.
  • An example format of an LVF-based spectral sensor is shown in FIGS 1, 2A and 2C.
  • the spectral sensing component is preferably implemented as part of a photodiode or a Complementary Metal-Oxide Semiconductor (CMOS) array detector package 15.
  • CMOS Complementary Metal-Oxide Semiconductor
  • the LVF is directly bonded to the detector array, which preserves the spectral resolution of the LVF. In this form the assembly does not require any form of resolution retaining optics. Sensors derived from these components based on the LVF can be used for absorption measurements in the mid-range UV, long-wave UV, the visible and the short-wave near infrared (NIR), as well as fluorescence measurements in the visible and NIR.
  • NIR near infrared
  • FIGS 14 and 15 Examples of data have been acquired in all of these modes, and example spectral response curves for the visible and NIR ranges are provided FIGS 14 and 15, respectively.
  • the short wave NIR provides good differentiation based on chemistry and composition based on vibrational overtones of the component molecules.
  • This spectral region can be applied to organic and inorganic compounds, and also aqueous solutions containing high concentrations of solutes.
  • the visible version for the spectral sensor can also be used.
  • the analysis may be performed with the addition of a reactive chemical reagent.
  • reagent-based chemistries are the basis for standard laboratory measurements, where the reagent and the sample are manually mixed prior to the analysis.
  • the analysis typically involves a visible (color) or fluorescence based measurement.
  • the reagent is immobilized within the tip of a Smart TipTM (FIG. 9) or within the tip/chamber of a Smart SamplerTM (FIG. 10).
  • the spectral sensor can be constructed from either a continuously variable filter (defined as the LVF) 14 or from a filter matrix or mosaic 15. This latter approach is usually optically more efficient and less expensive than the LVF approach. It is often more specific in application, but less versatile than the LVF system.
  • An illustrated example of a matrix-based spectral sensor 16 is provided in FIGS 2 and 3. The version shown is a 4-channel RGBW (Red-Green-Blue- White) sensing device, and is capable of handling a wide range of color-based applications. Custom versions of this sensor, featuring more than 4-optically selective channels can be used. New technologies, involving the deposition of the wavelength selective devices on the surface of the detector elements can be used to make application specific detection devices.
  • the mosaic can feature both the optical filter and the detector as discrete components.
  • Such devices can be assembled as hybrids, providing spectral detection in more than one spectral region, such as a combination of the UV, visible and NIR.
  • An example application can be for the measurement of bio-materials, such as proteins and amino acids, where one or more solid state excitation sources are used (such as 280 nm and 340 nm), and where detection is made in the UV (ca. 340 nm) and in the visible.
  • the sensor hardware for the present invention is not limited to silicon-based photo-sensing devices, and alternative detector arrays can be used, including InGaAs, PbS, PbSe, LiTaO 4 and also MEMS-based devices. Such devices would be considered for extensions into the longer wavelength NIR and for the mid-IR.
  • the format of the proposed sensor platform may be extended into these other spectral regions.
  • alternative optically transparent media may be required for the sample chamber and the optical conduit construction, and these can include materials such as quartz, sapphire and zinc selenide.
  • the onboard electronics that form part of the spectral engine (FIGS 3 to 5) provide for the primary data acquisition from the spectral sensing/detection devices.
  • the raw signal obtained needs to be conditioned and scaled.
  • This is effectively a transformation from the raw signals from the physical device to a spectral based data array (or spectrum), defined in wavelength (or energy) units (x-axis) and intensity units (y-axis).
  • a standardized or unified data format (UDF) is used to provide a well-defined start and end to the spectral data, and with a clearly delineated data interval (data point spacing).
  • the signal handling and these primary data transformations are shown as a symbolic representation in FIG 3, and are handled by what is defined as ⁇ P-1 (microprocessor function 1) 17.
  • ⁇ P-1 microprocessor function 1
  • This intensity data is further manipulated by one or more numerical functions, which normally include unique calibration data for the species being measured.
  • These additional mathematical functions are performed by the symbolic representation defined as ⁇ p-2 (microprocessor function 2) 18 and these are incorporated in what is defined as a method.
  • the methods which are downloaded into the memory (such as flash RAM) or the system, include data acquisition instructions, spectral data pre-processing, data extraction from the spectra, and also the subsequent calculations to provide the final answers.
  • ⁇ p-2 microprocessor function 2
  • chemometrics are common for such applications. These are used, as appropriate, and the calibration coefficients generated from the modeling are stored on memory (such as flash RAM) associated with one or more microprocessors associated with ⁇ P-2, FIG 3 (17 and 18), located on-board the sensor. Note that the functions for ⁇ P-1 and ⁇ P-2 can be combined in a single processor if required.
  • the flash RAM can be either present as separate memory components, or integrated into the microprocessors. It is noted that this numerical treatment is not unique to the NIR spectral measurement range, and the onboard computing facilities defined will also be used for resolving complex mixtures in other spectral regions served by the handheld devices described in this invention.
  • the component labeled ⁇ P-2 18 can also handle communications and display functions. Communications can be either hardwired, such as a standard serial COM device (UART function on mP-2) or as a USB device, or as wireless communications. The latter can be incorporated as components with separate functionality from ⁇ P-2 18.
  • the display function can include an onboard display for the handheld sensor, and can range from a simple multi-line display to a full-scale RGB XGA or other standard display device.
  • the spectral sensing elements can be fully integrated as a single entity or assembly on what are described as the sensing components in FIG 4.
  • This optical sensor assembly (or opto-board) includes the light source 19 and the spectral sensing element or detector 20, as also defined in paragraph [035]. These devices are optically isolated from each other by an optical mask fabricated from an optically opaque material 21, such as a carbon-filled elastomer. Example embodiments are shown in FIG 4 with circular and rectangular cross-sections. The choice of cross-section is dependent on final sensor configuration and application.
  • the main system electronics board 22 is directly coupled to the optical sensor assembly via either a hard connector on the back of the opto-board, or via internal cabling or flex-based connectors.
  • the source and spectral detection components are interfaced to the sample measurement cavity (or chamber) via light pipes, light guides or light conduits.
  • this is hard coupled to the sample chamber, and is designed to minimize optical crosstalk between the light source and the detection system.
  • the light guides can be in the form of optical fibers.
  • optical pathlengths can range from 0.1 cm to 10 cm and these are considered to be optimum, dependent on the material to be measured.
  • the selection of pathlength is usually method dependent and is a function of the color density of the solutions under study.
  • the longer pathlengths may be used for direct measurements made on organic chemicals, while shorter path lengths may be required for optically darker materials or water-based solutions.
  • the pathlength is defined within the integrated construction of the sensor measurement cavity thereby providing close-coupled sample chamber 24 (FIGS 5, 6 and 7).
  • a folded path construction as illustrated in FIGS 5, 6 and 7.
  • This folded pathlength 24a and 24b is obtained by the use of retro-reflective elements 25 located within the measurement cavity.
  • the example geometry is for a transmission-based measurement. Sample emission (such as fluorescence) or light scattering (such as turbidity) measurements can require alternative geometries, where the source and detection system are orthogonal (at 90 degrees) to each other, relative to the sample chamber.
  • the sample as a liquid (FIGS 6 and 7) or as a solid (FIG 8) interacts directly with the source and detection system within the sample area.
  • a reagent is involved with a liquid sample, in the configurations shown in FIGS 6 and 7, it is assumed that the reagent interacts with the liquid outside of the sample measurement area.
  • an alternative is to feature an immobilized reagent, which is located within the light path.
  • the reagent may be included within a transparent substrate as pads 24c in the light path within the measurement cavity (FIG 10) or on an opaque, reflective surface. In the latter case, the solid sampling approach of FIG 8 is required for the measurement.
  • Examples are pH or test-paper measurements, where the liquid sample reacts in situ with the reagent that is immobilized in a porous solid matrix, such as a sol gel or a membrane (organic or inorganic) or an absorbent paper matrix.
  • a porous solid matrix such as a sol gel or a membrane (organic or inorganic) or an absorbent paper matrix.
  • immobilized reagents are used and the optical measurement is made within the light path
  • special tips or sample chambers will be used with the immobilized reagent.
  • the immobilized reagent substrate is located within the fluid path of the tip.
  • the substrate including pads 24c is placed at the end of the entrance (and/or exit) points of the optical light guides.
  • the spectral engine is constructed as two separable parts.
  • the spectral sensing components and associated electronics (FIG 4) and the sample interface which is intended to be removable, and optionally disposable.
  • the spectral sensing components and the electronics are located within the main body of the sensor (FIGS 11, 12 and 13).
  • the sample chamber is located within the removable tip or sampler, which can be constructed in different forms dependent on the applications.
  • the device takes the form of a mechanical micro pipette where the sample is transported into the sensor tip via a built-in piston pump (or equivalent). In this form, the tip is constructed with the external appearance of a pipette tip 27 (FIG 6 and FIG 11).
  • the measurement module is independent of the sample transfer, which takes place within the completely separated sampler assembly.
  • the sampler has a common construction to a disposable pipette with a bellows (or bulb) style pumping (suction), and with the sample chamber mated on the side where the sample flow takes place.
  • the liquid fills the measurement cavity by the suction process, and any residual bubbles rise into the upper flow channel (or the bellows/bulb) and out of the optical path.
  • the sensor can also be configured to measure liquids by immersion or insertion (a dip tip configuration).
  • This form of sensor tip has a two part main construction, comprising an inner optically transparent part and an external optically opaque part.
  • the construction of the outside part is such that there is no light leakage from the outside into the internal sample chamber or measurement area.
  • the external part of the tip is constructed to eliminate the opportunity for external (ambient) stray light to enter the measurement zone.
  • both parts of the tip can be made from plastic materials (polymers). Also, in most cases, the materials can be fabricated from some form of co-extrusion process.
  • the internal reflective elements 25 for the sample chamber are to be fabricated from a reflective insert or with a reflective coating. In either case, the coating or the insert can be protected from the measurement medium by embedding within the plastic or by a protective top coat.
  • the sample tip 29 is designed to be open-ended.
  • the spectral sensor is intended for use with solid materials, where the sensor measures the reflected light from the solid sample surface. This may be used to measure reacted test strips (pH strips, water testing strips, medical test strips, for example), color from solid surfaces (powders, extended solids and fabrics, for example), or material composition, such as a transparent coating.
  • the application of the standard tips or samplers for liquids is intended to serve either applications that involve the direct spectral measurement of liquid samples, based on their own natural color or natural absorption (UV or NIR for example) or fluorescence.
  • the sensor will work as a spectrometer or photometer for a standard reagent-based measurement, where the reagent is mixed externally with the sample prior to sampling and measurement.
  • Alternative forms of tip or sampler known as a Smart TipTM, FIG 9, or as a Smart SamplerTM, FIG 10 can both be included.
  • the smart tip includes the reagent or reagents within the body of the tip.
  • the reagent can be located within the tip and/or within the measurement chamber.
  • the reagents are in an immobilized form 30, where they are either encapsulated within a water- soluble (or solvent-soluble) medium, or they are embedded within a water/solvent permeable membrane.
  • the reagent is mixed in situ as the sample is drawn into the entrance of the tip.
  • the mixture of sample and reagent is then drawn through a series of vanes 31, that provide a "tortuous" pathway, or mixing pre-chamber 31a, where the two components (reagent(s) and sample) are thoroughly mixed and are given time to react.
  • the mixed and reacted solution is then drawn into the measurement chamber.
  • the reagent can be alternatively be immobilized within an adsorbent structure where mixing occurs by passage through the adsorbent material (FIG 10, 30/31), or it can be immobilized in light transmitting pads 24c located within the light path of the measurement chamber (FIG 10).
  • this approach eliminates any external contact with the reagents (important if the regent materials are toxic or intrinsically corrosive), and it simplifies disposal.
  • the entire approach is environmentally friendly, eliminating the use of excess reagent materials and reducing the quantities of materials for disposal.
  • the specific regents can be identified by the external design or appearance of the tip, by using color coding, bar coding or by the use of a technology such as RFID.
  • FIGS 11, 12 and 13 Three example embodiments of the sensor system are illustrated, FIGS 11, 12 and 13.
  • the first is the fully self-contained pipette-based version FIG 11, is described as the SpectraPetteTM, which includes an integrated pumping system 32 for the sample transport.
  • the pumping can be implemented in the form of a simple piston pump.
  • a mechanized pumping based on an electrical micro pump (rotary or piezo, for example) can be used. Note that this format can support either the Standard measurement tips of the Smart Tips.
  • the main body of the sensor is fully self-contained and only has a light path interface with the sampler.
  • the complete measurement system is designed to be handheld, but is also designed to be freestanding on a solid surface.
  • the sensor is a simpler construction because there is not the requirement for the pumping action for sample introduction (FIG 13).
  • AU sensor formats are intended to be battery-powered, where standard dry cells or rechargeable batteries are used.
  • the main body of the sensor includes a display 33 and push-button user interface controls 34 for the selection of methods, and the display of results, and a minimum set of controls.
  • the display is not limited to a three-line format, and can display graphical information as well as alpha-numerics.
  • the controls 34 can include functions such as power on-off, method selection, measurement activation, and transmit (for the transmission of results/data).
  • Automatic features can include auto-power down, and auto- transmit to a local central PC for data logging, of both raw and processed spectral data.
  • the approach offered is described as being based on a spectral engine (FIG 1), which is further illustrated in its final embodiments in FIGS 11,12 and 13.
  • the spectral engine includes the spectral sensing device (described above) 14 and 15, and the energy source 10 and 19, which can be either a broadband or narrowband source, dependent on the mode of measurement (broadband sources are used for NIR and visible absorption, narrowband sources are used for turbidity and fluorescence). White LEDs, LED arrays and tungsten bulbs are used as example broadband sources, and individual LEDs and semiconductor laser devices are used as narrowband sources.
  • Another component of the spectral engine is the sample interface, which is typically a cavity or chamber 24.
  • the sample chamber is optimized in size based on the physical dimensions of the spectral engine sample interface.
  • the sizes of the detection devices are, for example, 1 mm x 8 mm 15 and approximately 3 mm x 3 mm (matrix sensor 16). Scaling the sample cell to these physical dimensions can produce sample chamber volumes as low as 80 microliters.
  • the advantage gained here is that a minimum sample size is required, which effectively eliminates any sample temperature effects, and significantly reduces the amount of reagents that have to be dispensed for reagent-based applications.
  • the volume requirement for reagents can be reduced down by as much as 1000 times, which reduces reagent consumption and operating costs.
  • the final critical set of components of the spectral engine is the electronics.
  • FIG 3 An example of the functional electronics is provided in FIG 3, which are physically located within the total sensor body as illustrated in FIGS 5 to 8 as 22. Up to two microprocessors, and possibly more can be used for the initial data handling (processor #1 17, and then the data massaging processor #2 18).
  • the final processor 18 can feature onboard memory to store methods, calibrations and results, and can handle communications to displays (if required), external devices via serial connections and also wireless communications if the option is used.
  • a single advanced processor is a practical alternative to the two processor format.
  • the spectral sensor implementation is based on basic two-part construction featuring the main spectral sensing system, with common display and controls, and a disposable component; a tip FIGS 11 and 13, or a sampler FIG 12.
  • Two main formats are offered; one with sample transport, in the format of a micro-pipette (FIG 11) or a disposable pipette (FIG 12), and the other as a dip (insertion) or surface measurement device (FIG 13).
  • the function of the sensor is defined in terms of the tip or sampler (27, 28 or 29), and the method of measurement selected from the integrated display 33.

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Abstract

La présente invention se rapporte à un moteur de détection spectral intégré recourant à des sources d'énergie et à des détecteurs contenus dans un boîtier unique, qui comprend une optique d'interfaçage d'échantillon et un circuit électronique d'acquisition et de traitement. Grâce à son intégration dans un format portatif, le capteur miniaturisé selon l'invention est optimisé pour des mesures spécifiques en laboratoire et sur le terrain (voir figure). Les composants de conception et de fabrication sont adaptés à une fabrication en grand volume. La sélectivité spectrale est assurée soit par des filtres optiques variables continus soit par des dispositifs à matrice de filtre. La réponse du capteur couvre la plage s'étendant de 200 nm à 25 µm, en fonction de divers détecteurs solides. La plage de longueur d'onde peut être élargie par l'utilisation de dispositifs à matrice de filtre. Les mesures peuvent être effectuées par transmittance/absorbance, par turbidité (diffusion de la lumière) et par fluorescence (émission). Le traitement embarqué des données consiste en l'acquisition de données brutes, en la réduction des données et en la production des résultats calculés. Le capteur selon l'invention peut être appliqué à l'exécution d'analyses dans les domaines de l'eau, de l'environnement, des produits alimentaires et des boissons, de la chimie et du pétrole, et de la médecine. Ces domaines d'application peuvent être élargis pour englober diverses applications de terrain et axées sur le consommateur.
EP06838711A 2005-11-30 2006-11-30 Systeme de detection integre portatif pour mesures spectrales Withdrawn EP1955033A4 (fr)

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WO2010027982A2 (fr) * 2008-09-02 2010-03-11 Microptix Technologies, Llc Mécanisme adaptateur pour dispositif portable de détection spectrale
US8248611B2 (en) * 2010-03-31 2012-08-21 Ecolab Usa Inc. Handheld optical measuring device and method of use
US8352207B2 (en) 2010-03-31 2013-01-08 Ecolab Usa Inc. Methods for calibrating a fluorometer
WO2016063284A2 (fr) 2014-10-23 2016-04-28 Verifood, Ltd. Accessoires pour spectromètre portatif
WO2018015951A1 (fr) 2016-07-20 2018-01-25 Verifood, Ltd. Accessoires pour spectromètre portatif
CN107271385A (zh) * 2017-06-12 2017-10-20 中科谱光科技（北京）有限公司 一种手环式吸光度测量仪
DE102018204837A1 (de) * 2017-08-09 2019-02-14 Robert Bosch Gmbh Spektrometrische Messvorrichtung und Verfahren zur Analyse eines Mediums unter Verwendung einer spektrometrischen Messvorrichtung
CN110672534A (zh) * 2019-10-18 2020-01-10 湖南国天电子科技有限公司 海洋水质测试系统、方法及装置
KR20230011952A (ko) * 2020-05-20 2023-01-25 와이에스아이 인코포레이티드 스위프 주파수 형광계
CN115825024B (zh) * 2022-10-10 2024-05-24 中国农业大学烟台研究院 一种水质现场快速检测方法

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AUPP748398A0 (en) * 1998-12-03 1998-12-24 Varian Australia Pty Ltd Uv-vis spectrophotometry
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WO2007064820A3 (fr) 2009-05-07
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