GB2402493A - Optical relay with deflectors for analysing samples - Google Patents

Optical relay with deflectors for analysing samples Download PDF

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Publication number
GB2402493A
GB2402493A GB0312751A GB0312751A GB2402493A GB 2402493 A GB2402493 A GB 2402493A GB 0312751 A GB0312751 A GB 0312751A GB 0312751 A GB0312751 A GB 0312751A GB 2402493 A GB2402493 A GB 2402493A
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GB
Grant status
Application
Patent type
Prior art keywords
sample
relay
optical
radiation
window
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.)
Granted
Application number
GB0312751A
Other versions
GB2402493B (en )
GB0312751D0 (en )
Inventor
John Arthur Amner
Peter Edmund Rueben Mucci
Nicholas Imbert
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.)
Ford Global Technologies LLC
Original Assignee
Ford Global 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

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Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01JMEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRA-RED, VISIBLE OR ULTRA-VIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/02Details
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01JMEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRA-RED, VISIBLE OR ULTRA-VIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/02Details
    • G01J3/0205Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows
    • G01J3/0208Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows using focussing or collimating elements, e.g. lenses or mirrors; performing aberration correction
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01JMEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRA-RED, VISIBLE OR ULTRA-VIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/02Details
    • G01J3/0205Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows
    • G01J3/021Optical elements not provided otherwise, e.g. optical manifolds, diffusers, windows using plane or convex mirrors, parallel phase plates, or particular reflectors
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01JMEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRA-RED, VISIBLE OR ULTRA-VIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/02Details
    • G01J3/0289Field-of-view determination; Aiming or pointing of a spectrometer; Adjusting alignment; Encoding angular position; Size of measurement area; Position tracking
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01JMEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRA-RED, VISIBLE OR ULTRA-VIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/02Details
    • G01J3/0291Housings; Spectrometer accessories; Spatial arrangement of elements, e.g. folded path arrangements
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01JMEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRA-RED, VISIBLE OR ULTRA-VIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/02Details
    • G01J3/08Beam switching arrangements
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01JMEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRA-RED, VISIBLE OR ULTRA-VIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/28Investigating the spectrum
    • G01J2003/2866Markers; Calibrating of scan
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using infra-red, visible or ultra-violet light
    • G01N21/17Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/35Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infra-red light
    • G01N2021/3595Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infra-red light using FTIR
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using infra-red, visible or ultra-violet light
    • G01N21/17Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/35Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infra-red light
    • G01N21/3563Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using infra-red light for analysing solids; Preparation of samples therefor

Abstract

An optical relay 10 for an Infra Red spectrometer is disclosed having a housing to be located between the source and detection windows of a spectrometer. The relay 10 comprises a sample window 12 against which a sample may be placed for analysis by the spectrometer. The relay 10 also has a sample holder 14 for introducing a sample into the housing for analysis by the spectrometer. Two systems of deflectors 23,24,26,28 are arranged within the housing for selectively deflecting the IR radiation of the spectrometer to analyse a sample placed against the sample window 12 or a sample introduced into the housing by means of the sample holder 14. The IR radiation may also be directed using concave mirrors 30,36. The apparatus are used in the identification of plastics material.

Description

Plastics Identification

Field of the invention

The present invention relates to identification of plastics materials based on IR spectroscopy.

Background of the invention

lo It is environmentally highly desirable to be able to recycle articles made of plastics materials. Recycling not only solves the problem of how to dispose of plastics articles but also reduces the depletion of the world's resources of fossil fuels. There is however a need to be is able to identify plastics material reliably so that different materials may be separated from one another.

Certain material, for example PET and PVC, which can be visually indistinguishable from one another, will contaminate one another. If mixed, these resins can release hydrochloric gases and PET resin is ruined if mixed with even a very small proportion of PVC.

It is already known to use IR (infrared) spectroscopy to distinguish between different plastics materials. This is based on the fact that each plastics material has a characteristic IR absorption spectrum and by analysing the spectrum of IR radiation transmitted through or reflected by a plastics material one can determine its composition.

Known spectrometers have a recess defined between two facing surfaces. IR radiation is emitted from a source window in one of the surfaces. After interacting with the analysis sample, the IR radiation is received in an aligned detection window in the other surface. Such a configuration is intended for transparent or translucent samples in which the IR radiation passes through the sample. - 2

To analyse opaque samples, it is known, for example from EP 0713082, to place in the recess on optical relay containing a system of deflectors. The deflectors intercept the IR radiation from the source window of the spectrometer and deflect it towards a nozzle-like sample window. When a sample to be analysed is placed against the window, the radiation reflected from the surface of the sample is deflected by the deflectors within the optical relay to the detection window of the spectrometer. Such an optical relay is not well suited to the analysis of samples that are in granular form because the incident radiation is scattered instead of being uniformly reflected by the sample.

An optical relay better suited for granular material is described in US-A4,479,058. Here, the sample is introduced by means of a sample holder into the housing of the optical relay and the latter comprises a system of deflectors that once again deflects the IR radiation from the source window onto the sample and deflects the reflected radiation towards the detection window of the spectrometer. While this relay can be used to analyse small samples, it is unsuitable for larger samples which will not fit within the sample holder.

Object of the invention In a plastics recycling station, the material for recycling can come in all shapes and sizes ranging from a large item such as a vehicle bumper to granules and the aim of the present invention is to provide a versatile optical cell that can be used with a wide variety of samples.

Summary of the invention

According to the present invention, there is provided an optical relay for an IR spectrometer comprising a housing to be located between the source and detection windows of a spectrometer, the relay comprising a sample window against - 3 which a sample may be placed for analysis by the spectrometer and a sample holder for introducing a sample into the housing for analysis by the spectrometer, wherein two systems of deflectors are arranged within the housing for selectively deflecting the IR radiation of the spectrometer to analyse a sample placed against the sample window or a sample introduced into the housing by means of the sample holder.

lo By providing an optical relay that has both a sample window and a sample holder, the invention enables both solids with flat surfaces and granules to be analysed by means of the same spectrometer, without the need to interchange optical relays. Removing one optical relay and fitting the spectrometer with another is time consuming.

Furthermore, optical relays are delicate instruments that can easily be damaged during their removal from and mounting on a spectrometer and while they are not in use.

The recess at the front of a spectrometer within which the optical relay is received can be regarded as a hollow cube with its front and top walls missing. The horizontal bottom wall of the cube is a base plate on which the optical relay is supported, the vertical side walls of the cube are the surfaces containing the source window and the detection window and the vertical rear wall is formed by the housing of the spectrometer. Such terms as "front", "top", "bottom", "forward", "above", "below", "vertical" and "horizontal" as used herein are all to be construed by reference to the orientation of the walls of the recess as described above.

In a preferred embodiment of the invention, the sample window is positioned forward of the line connecting the source and detection windows and the IR radiation is deflected in a horizontal plane to and from the sample window, whereas the sample holder is arranged above the line connecting the source and detection windows and the IR - 4 - radiation is deflected in a vertical plane to and from the sample in the sample holder.

The preferred embodiment of the invention enables the radiation paths associated with the sample window and the sample holder to be contained within the same optical relay by arranging the optical paths in orthogonal planes.

Preferably, the optical relay comprises deflectors that lo are movable in synchronism with the sample holder so that the radiation light path through the optical relay is selected automatically in dependence upon whether the sample holder is pushed in or pulled out. In this way, the operation of the optical relay is rendered fool proof. While a sample is inserted into the optical relay by pushing in the sample holder, the spectrometer will be automatically configured to analyse the radiation reflected from the sample. With the sample holder pulled out, on the other hand, the IR radiation will automatically be directed toward the sample window for analysis of large sample placed against the window.

Brief description of the drawings

The invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of an optical relay in accordance with the invention, JO Figures 2A and 2B are a schematic plan views of a carrier movable with the sample holder, Figure 2A showing it in its position when the sample holder is pulled out and Figure 2B showing it in its position when the sample holder is pushed in, and Figure 3 is a schematic vertical section through the optical relay showing the path of the IR radiation when analysing a sample supported on the sample holder. - 5 -

Detailed description of the preferred embodiment -

Figure 1 shows an optical relay 10 designed and dimensioned to be inserted in the recess at the front of an = IR spectrometer (not shown). The construction and method of - operation of an IR spectrometer are well documented in the prior art (see for example the two references cited above) and will not be described further in the present context.

The optical relay 10 is essentially a box containing a - system of deflectors. At the front of the box is a sample - window 12, also termed a nozzle on account of its conical shape. Above the nozzle 12 is a sample holder 14 that is shown in Figure 1 in its retracted or pulled out position.

When a granular sample is to be analysed, it is placed in - the sample holder 14 and the latter is then pushed in.

On its opposite sides, the optical relay has two - openings of which only the opening 16 is seen in Figure 2. A - similar opening is formed on the opposite side of the relay 10. The openings line up with the source and detection - windows of the IR spectrometer.

When the sample holder 14 is pulled out, the IR radiation entering from the source window is deflected in a horizontal plane (as will be described in greater detail below by reference to Figure 2A) to emerge from the nozzle 12. There it is reflected by the sample and the reflected radiation is once again deflected in a horizontal plane to - leave the optical relay through the opening 16 and enter the detection window of the spectrometer. = When the sample holder is pushed in, the IR radiation entering from the source window is deflected in a vertical plane (as will be described in greater detail below by reference to Figures 2B and 3) to fall on the sample resting on the sample holder 14 within the optical relay. The radiation reflected by the sample is once again deflected in - 6 - a vertical plane to leave the optical relay through the opening 16 and enter the detection window of the spectrometer.

References herein to deflection of IR radiation are intended to include both reflection and refraction.

Furthermore, reflection may either occur at a silvered mirror or at the surface of a prism by total internal reflection.

In the preferred embodiment of the invention, the path followed by the radiation through the optical relay 10 is determined by whether the sample holder 14 is pushed in or pulled out. A carrier 20 is mounted within the optical relay 10 which supports four movable deflectors 22, 24, 26 and 28.

All the remaining deflectors within the optical relay 10 are stationary.

The deflectors 22 and 24 deflect the IR radiation in a horizontal plane as shown in Figure 2A. IR radiation entering from the left in Figure 2 from the source window of the spectrometer is deflected forwards by the deflector 22 onto a concave mirror 30. This mirror 30 focuses the radiation, which is deflected by a further stationary deflector 32 onto the sample arranged at the sample window 12.

The radiation reflected by the sample at the sample window 12 follows a path which is a mirror image of that followed by the incident radiation, that is to say it is reflected by a stationary deflector 34 onto a concave mirror 36 and then by way of the second deflector 24 supported on the movable carrier 20 towards the detection window of the spectrometer.

When a granular sample is to be analysed, it is placed on the sample holder 14 which is then pushed into the - 7 optical relay 10. The movement of the sample holder 14 is accompanied by a movement of the carrier 20 to the position shown in Figures 2B and 3. The deflector 26 on the carrier this time deflects the incident radiation in a vertical plane so that the reflected rays are normal to the plane of Figure 2B. As shown in Figure 3, the IR radiation is then focussed by a concave reflector 40 onto the sample supported on the sample holder 14. The radiation scattered by reflection from the surface of the granular sample is lo reflected by the concave mirror 40 on to the second deflector 28 supported on the movable carrier 20 which in turn directs the radiation towards the detection window of the spectrometer.

].5 It is to be preferred for the detection window not to receive IR radiation directly from the source radiation. To this end, in the illustrated embodiment of the invention, a barrier 42 is positioned above the sample holder and a further barrier, shown schematically at 44 in Figure 2A and JO 2B, is arranged on the movable carrier 20 between the deflectors of each pair 22, 24 and 26, 28. : - 8

Claims (6)

1. An optical relay for an IR spectrometer comprising a housing to be located between the source and detection windows of a spectrometer, the relay comprising a sample window against which a sample may be placed for analysis by the spectrometer and a sample holder for introducing a sample into the housing for analysis by the spectrometer, wherein two systems of deflectors are arranged within the lo housing for selectively deflecting the IR radiation of the spectrometer to analyse a sample placed against the sample window or a sample introduced into the housing by means of the sample holder.
2. An optical relay as claimed in claim 1, wherein the sample window is positioned forward of the line connecting the source and detection windows and the IR radiation is deflected in a horizontal plane to and from the sample window, whereas the sample holder is arranged above the line connecting the source and detection windows and the IR radiation is deflected in a vertical plane to and from the sample in the sample holder.
3. An optical relay as claimed in claim 1 or 2, wherein the optical relay comprises deflectors that are movable in synchronism with the sample holder so that the radiation light path through the optical relay is selected automatically in dependence upon whether the sample holder is pushed in or pulled out.
4. An optical relay as claimed in any preceding claim, wherein at least one barrier is provided to prevent IR radiation from the source window of the spectrometer from reaching the detection window without being reflected by the sample to be analyzed. - 9
5. An optical relay as claimed in any preceding claim wherein at least some of the deflectors are mirrors.
6. An optical relay constructed arranged and adapted to operate substantially as herein described with reference to and as illustrated in the accompanying drawings.
GB0312751A 2003-06-04 2003-06-04 Plastics identification Active GB2402493B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB0312751A GB2402493B (en) 2003-06-04 2003-06-04 Plastics identification

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB0312751A GB2402493B (en) 2003-06-04 2003-06-04 Plastics identification

Publications (3)

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GB0312751D0 GB0312751D0 (en) 2003-07-09
GB2402493A true true GB2402493A (en) 2004-12-08
GB2402493B GB2402493B (en) 2006-06-14

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4479058A (en) * 1981-12-02 1984-10-23 Bruker Analytische Messtechnik Gmbh Auxiliary unit for carrying out reflection measurements using an IR spectrometer
US4594509A (en) * 1983-01-31 1986-06-10 Bruker Analytische Messtechnik Gmbh Infrared spectrometer
US5048970A (en) * 1990-06-29 1991-09-17 Nicolas J. Harrick Optical attachment for variable angle reflection spectroscopy
US5499095A (en) * 1992-10-02 1996-03-12 Bruker Analytische Mebtechnik Gmbh Fourier spectrometer with exchangeable entrance and exit ports allowing for both internal and external radiation sources
WO2001067037A1 (en) * 2000-03-08 2001-09-13 Thermo Nicolet Corporation Multifunctional fourier transform infrared spectrometer system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4479058A (en) * 1981-12-02 1984-10-23 Bruker Analytische Messtechnik Gmbh Auxiliary unit for carrying out reflection measurements using an IR spectrometer
US4594509A (en) * 1983-01-31 1986-06-10 Bruker Analytische Messtechnik Gmbh Infrared spectrometer
US5048970A (en) * 1990-06-29 1991-09-17 Nicolas J. Harrick Optical attachment for variable angle reflection spectroscopy
US5499095A (en) * 1992-10-02 1996-03-12 Bruker Analytische Mebtechnik Gmbh Fourier spectrometer with exchangeable entrance and exit ports allowing for both internal and external radiation sources
WO2001067037A1 (en) * 2000-03-08 2001-09-13 Thermo Nicolet Corporation Multifunctional fourier transform infrared spectrometer system

Also Published As

Publication number Publication date Type
GB2402493B (en) 2006-06-14 grant
GB0312751D0 (en) 2003-07-09 grant

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Effective date: 20090223