Patent Description:
An identification apparatus that optically identifies properties of a sample using spectroscopic analysis is known. Such an identification apparatus is installed in a conveyance path for conveying a plurality of samples and is used to inspect products and to sort wastes.

Spectroscopic analysis does not always require processes, such as vacuum decompression, atmosphere control, immersion in liquid, and atmosphere management for drying that limit the throughput, and properties of a sample can be identified under an atmospheric atmosphere. Thus, attempts to apply the spectroscopic analysis to the sorting of waste resins have been made in recent years.

Known types of spectroscopic analysis are infrared absorption spectroscopy and Raman scattering spectroscopy. Infrared absorption spectroscopy acquires an absorption spectrum of a sample with respect to incident light containing an infrared wavelength band. Raman scattering spectroscopy acquires a scattering spectrum of a sample with respect to incident light containing an ultraviolet wavelength band. Raman scattering spectroscopy is less likely to be affected by light attenuation due to the thickness of the sample and is therefore used in identifying wastes of different sample sizes. A Raman scattering spectroscopic method of dispersing Raman scattered light uses Raman shifts specific to atomic bonds constituting a hydrocarbon and is therefore suitable for use in identifying a resin.

The intensity of Raman scattered light is lower by several orders of magnitude than elastic scattered components (Rayleigh scattered light) contained in secondary light, so that a method of converging primary light and irradiating a sample with the converged light is employed to increase the detection sensitivity per unit area. There is a known sorting apparatus that sorts samples into a target sample and others based on whether a predetermined target condition is satisfied based on a detected spectrum.

<NPL>) discusses a waste resin identification apparatus including a light collecting unit, a spectroscopic element, and a charge-coupled device (CCD) image sensor having <NUM>-by-<NUM> (row direction by column direction) elements arrayed in a two-dimensional matrix. The identification apparatus discussed in <NPL>) projects an optical spectrum from the spectroscopic element along a lengthwise direction (row direction) of the CCD image sensor. <NPL>) further discusses acquisition of a spectral image at high speed by reading an optical spectrum projected from the spectroscopic element in the column direction. <CIT> discusses an identification apparatus including a plurality of light collecting units, a spectroscopic element, and a two-dimensional imaging unit. The identification apparatus discussed in <CIT> is reduced in size by consolidating apparatuses following the plurality of light collecting units into a single spectroscopic element and a single two-dimensional imaging unit. The identification apparatus discussed in <CIT> uses a rolling shutter complementary metal oxide semiconductor (CMOS) image sensor as the two-dimensional imaging unit to reduce interaction between spectral images projected in parallel in a column direction.

The identification apparatuses discussed in<NPL>) and <CIT> are limited in spectral resolution in the wavenumber direction by the resolution of the spectroscopic element and the number of projection pixels on the two-dimensional imaging unit.

Meanwhile, a Raman scattering spectrum has a Raman shift peak wavenumber corresponding to a specific functional group in the wavenumber range of <NUM>-<NUM> to <NUM>-<NUM>. <FIG> illustrates a Raman scattering spectrum of polystyrene as an example of a hydrocarbon contained in a waste resin. Characteristics peak shifts in the wavenumber range of <NUM>-<NUM> to <NUM>-<NUM> are not uniform but uneven, and the wavenumber range is divided in the wavenumber direction. It is known to divide the Raman spectroscopy wavenumber range into three regions i.e., a fingerprint region (<NUM>-<NUM> to <NUM>-<NUM>), a silent region, and a C-H stretch region (<NUM>-<NUM> to <NUM>-<NUM>) from low wavenumbers toward high wavenumbers. Useful peak shifts appear less frequently in the silent region (<NUM>-<NUM> to <NUM>-<NUM>) between the fingerprint region and the C-H stretch region than in the fingerprint region and the C-H stretch region on spectral identification.

Thus, the number of light detection elements corresponding to the silent region of the optical spectrum projected to the imaging units of the identification apparatuses discussed in <NPL>) and <CIT> are not effectively used in material identification, and the use efficiency of the imaging unit is decreased as illustrated in <FIG>. In other words, the number of light detection elements corresponding to the silent region is <NUM>/<NUM> to <NUM>/<NUM> the number of light detection elements corresponding to the entire region of the spectrum projected in the row direction, and therefore the spectral identification capacity is decreased by <NUM>/<NUM> to <NUM>/<NUM>.

<CIT> discusses an optical spectrograph utilizes a plurality of holographic transmission optical gratings operative to receive an incoming source of light to be analyzed, and diffract the light such that different spectral components impinge upon spatially separated regions of an opto-electronic detector. Various grating configurations are disclosed, including a physical stack of gratings conducive to extreme compactness, as well as a spaced-apart configuration used to preclude spectral cross talk in certain configurations. Diverging light emerging from a fiber-optic bundle is collimated by a first lens assembly prior to passing through the gratings, and a second lens assembly is used to focus the diffracted light onto the detectors, preferably in the form of a two-dimensional CCD array.

<CIT> discusses a Raman spectrometer having a charge-coupled device detector, an incoming beam containing a spectrum of Raman scattered light is dispersed by a diffraction grating. Different parts of the spectrum are split into separate optical paths by edge filters and a mirror. These components are tilted at different vertical angles, so that after the beams have been dispersed by the diffraction grating, they form partial spectra, one above the other on the CCD. This enables several consecutive parts of a widely dispersed spectrum to be viewed simultaneously on the CCD at high resolution.

<CIT> discusses a multi-wavelength laser source that uses a single unfocused pulse of a low intensity but high power laser over a large sample area to collect Raman scattered collimated light, which is then Rayleigh filtered and focused using a singlet lens into a stacked fiber bundle connected to a customized spectrograph, which separates the individual spectra from the scattered wavelengths using a hybrid diffraction grating for collection onto spectra-specific sections of an array photodetector to measure spectral intensity and thereby identify one or more compounds in the sample.

<CIT> discusses A system and method for analyzing biological samples. A system may comprise an illumination source to illuminate at least one location of a biological sample and generate at least one plurality of interacted photons, at least one mirror for directing the interacted photons to a detector. The detector may be configured to generate at least one Raman data set representative of the biological sample. The system and method may utilize a FAST device for multipoint analysis or may be configured to analyze a sample using a line scanning configuration.

The present invention is directed to an identification apparatus including a spectroscopic element as set out in the appended set of claims, situated to effectively disperse collected light and an imaging unit. Specifically, the present invention is directed to an identification apparatus that ensures a spectral resolution of a wavenumber band useful in identifying properties of a sample.

According to an aspect of the present invention, there is provided an identification apparatus as specified in claims <NUM> to <NUM>.

Various exemplary embodiments of the present invention will now be described with reference to the drawings.

An identification apparatus according to a first exemplary embodiment will now be described with reference to <FIG>, <FIG>, <FIG>. <FIG> is a diagram schematically illustrating a configuration of an identification apparatus <NUM> according to the present exemplary embodiment. <FIG> is a detailed partial view illustrating a spectral information acquisition unit <NUM> of the identification apparatus <NUM> illustrated in <FIG>. <FIG> is a diagram illustrating a projection of optical spectra 280sl and 280sh to an imaging unit <NUM>. <FIG> is a diagram illustrating a relationship between light detection element numbers in a row direction 172r of the imaging unit <NUM> and wavenumbers of optical spectra projected in the row direction 172r. The light detection element numbers are also referred to as "row direction addresses of light detection elements" or "row direction numbers of light detection elements".

In <FIG>, a z-direction corresponds to a vertical direction and a gravity direction, an x-direction corresponds to a conveyance direction dc, a y-direction corresponds to a conveyance width direction dw, and an xy-plane corresponds to a horizontal surface. The conveyance width direction dw is parallel to a conveyance surface <NUM> and corresponds to a direction orthogonal to the conveyance direction dc.

The identification apparatus <NUM> includes an irradiation unit <NUM> as illustrated in <FIG>. The irradiation unit <NUM> irradiates a sample 900i conveyed in the conveyance direction dc with irradiation light <NUM> to focus the irradiation light <NUM> on the sample 900i. The sample 900i is fed to a conveyance unit <NUM> by a feeder <NUM> and conveyed along the conveyance direction dc by the conveyance unit <NUM>. The irradiation light <NUM> is also referred to as converged light <NUM> or primary light <NUM>.

The identification apparatus <NUM> includes a light collecting unit <NUM> corresponding to the irradiation unit <NUM> as illustrated in <FIG>. The light collecting unit <NUM> collects scattered light from the sample 900i. The identification apparatus <NUM> also includes an acquisition unit <NUM> as illustrated in Fig. 1A. The acquisition unit <NUM> acquires identification information for identifying properties of the sample 900i based on the light collected by the light collecting unit <NUM>.

The identification apparatus <NUM> also includes the conveyance unit <NUM> and a discrimination apparatus <NUM> situated downstream of the conveyance unit <NUM> in the conveyance direction dc, as illustrated in <FIG>. The conveyance unit <NUM> includes a conveyer belt that conveys the sample 900i at a conveyance velocity vc in the x-direction.

A spectral information acquisition unit included in the identification apparatus <NUM> and having a spectroscopic element and an imaging unit according to a feature of the present invention will now be described in detail with reference to <FIG>.

The identification apparatus <NUM> includes the spectral information acquisition unit <NUM> configured to acquire spectral information about light collected from the sample 900i. The spectral information acquisition unit <NUM> is a unit that acquires a Raman shift from a difference in wavenumber between Raman scattered light contained in secondary light from the sample 900i and excitation light contained in primary light.

The spectral information acquisition unit <NUM> includes the irradiation unit <NUM> and the light collecting unit <NUM> as illustrated in <FIG> and <FIG>. The irradiation unit <NUM> irradiates the sample 900i with the irradiation light <NUM>, and the light collecting unit <NUM> collects the secondary light from the sample 900i. The irradiation unit <NUM> and the light collecting unit <NUM> according to the present exemplary embodiment are situated on the same axis, and the irradiation unit <NUM> is optically coupled to a light source <NUM> including a laser light source via an optical fiber <NUM>. The light collecting unit <NUM> is optically coupled to a spectral image acquisition unit <NUM> to enable the spectral information acquisition unit <NUM> to acquire optical information reflecting a material contained in the sample 900i.

<FIG> is a diagram schematically illustrating an example of a configuration of the spectral information acquisition unit <NUM>. The spectral information acquisition unit <NUM> includes a light collecting unit <NUM> having the irradiation unit <NUM> and the light collecting unit <NUM>. The irradiation unit <NUM> irradiates the sample 900i with light, and the light collecting unit <NUM> collects Raman scattered light from the sample 900i. The irradiation unit <NUM> and the light collecting unit <NUM> are situated on the same axis on the sample side (object side) when viewed from a dichroic mirror <NUM>, and a positional deviation is less likely to occur between a center of an irradiation spot and a center of scattered light to be collected even in a case where an irradiated surface of the sample 900i has a difference in height or is tilted.

The irradiation unit <NUM> is situated above the conveyance unit <NUM> and has a focal distance DF to form a focal plane <NUM> at a position at a predetermined distance from the conveyance surface <NUM> of the conveyer belt.

The irradiation unit <NUM> is situated to focus the irradiation light <NUM> on an upper side of the sample 900i to increase the scattering intensity of Raman scattered light, which is weaker by several orders of magnitude than Rayleigh scattered light. A unit including the irradiation unit <NUM> and the light source <NUM> is also referred to as an irradiation optical system.

The irradiation unit <NUM> includes an objective lens <NUM>, the dichroic mirror <NUM>, a collimator lens <NUM>, a cylindrical lens <NUM>, and a reflection mirror <NUM> as illustrated in <FIG>. The objective lens <NUM> employs a convex lens, a collimator lens, a concave lens, and/or a zoom lens.

Synthetic quartz can be used as a glass material for the collimator lens <NUM>, the cylindrical lens <NUM>, and the objective lens <NUM>. The collimator lens <NUM>, the cylindrical lens <NUM>, and the objective lens <NUM> are irradiated with high-output light from a semiconductor laser <NUM>, but use of synthetic quartz as a material for these glass lenses can reduce background components of fluorescence and Raman scattered light.

The objective lens <NUM> acts as a condenser lens that condenses light from the laser light source <NUM> to the sample 900i in the irradiation unit <NUM>. The objective lens <NUM> forms the focal plane <NUM> at a focal distance DF from the objective lens <NUM>, a focal point (focal spot) with a focal diameter ϕ (not illustrated), and a focal depth ΔDF correspondingly to a numerical aperture NA.

The collimator lens <NUM> and the cylindrical lens <NUM> reduce the spread of emitted light from the laser light source <NUM> and shape the light into parallel light. The cylindrical lens <NUM> can use another optical element for collimating such as an anamorphic prism pairs. Further, a wavelength filter such as a laser line filter can be provided at the position of a pupil surface of the irradiation unit <NUM>. This improves wavelength characteristics of light with which the sample 900i is irradiated by the irradiation unit <NUM>.

As illustrated in <FIG>, at least a portion of the irradiation unit <NUM> can be shared with the light collecting unit <NUM>. Since the light collecting unit <NUM> and the irradiation unit <NUM> according to the present exemplary embodiment are situated on the same axis, the objective lens <NUM> and the dichroic mirror <NUM> are shared by the light collecting unit <NUM> and the irradiation unit <NUM>.

The light source <NUM> is a light source that emits excitation light to the irradiation unit <NUM> via the optical fiber <NUM>. The irradiation optical system that disperses Raman scattered light uses a laser light source with a wavelength of <NUM> to <NUM> as the light source <NUM>. In Raman scattering, the excitation efficiency increases at shorter wavelengths, and fluorescence components to be a background decrease at longer wavelengths.

A wavelength selected as an excitation wavelength of a laser light source applied to the light source <NUM> is desirably a wavelength from which a difference in Raman shift between a target material and a non-target material is distinctively obtained, and there is a case where at least one of <NUM>, <NUM>, <NUM>, and <NUM> is used. While use of the semiconductor laser <NUM> as a light source of the irradiation unit <NUM> is described herein, the light source is not limited to that described herein, and another laser light source such as a semiconductor excited solid-state laser or a gas laser can be used.

The light collecting unit <NUM> is situated above the conveyance surface <NUM> to collect the secondary light emitted from a top surface of the sample 900i conveyed by the conveyance unit <NUM>. In other words, the light collecting unit <NUM> is situated above the conveyance unit <NUM> corresponding to an irradiation region of the irradiation light <NUM> emitted from the irradiation unit <NUM> to collect the secondary light from the top surface of the sample 900i conveyed through the irradiation region.

The light collecting unit <NUM> includes the objective lens <NUM>, the dichroic mirror <NUM>, an imaging lens <NUM>, and an optical fiber <NUM>. The objective lens <NUM> of the light collecting unit <NUM> includes a convex lens, a collimator lens, a concave lens, and/or a zoom lens as those included in the irradiation unit <NUM>. The light collecting unit <NUM> may include a wavelength filter, such as a band-pass filter or a long-pass filter to reduce excitation light components contained in the primary light, in order to reduce unnecessary light in spectroscopic measurement.

The light collecting unit <NUM> employs an objective lens having a large numerical aperture to ensure light collection efficiency. An objective lens with a numerical aperture of <NUM> or more to <NUM> or less is employed as the objective lens <NUM> of the light collecting unit <NUM>. More specifically, an objective lens B-<NUM> manufactured by SCHOTT having an effective lens diameter of <NUM>, a focal distance of <NUM>, and a numerical aperture of <NUM> can be used as the objective lens <NUM>.

The spectral image acquisition unit <NUM> includes a branch portion <NUM>, imaging lenses <NUM> and <NUM>, band-pass filters <NUM> and <NUM>, spectroscopic elements <NUM> and <NUM>, and the imaging unit <NUM> in this order from the light collecting unit <NUM> side as illustrated in <FIG>. In the present exemplary embodiment, the letters l (the lowercase letter of "L" of the alphabet) and h are added at the end of each reference numeral to indicate the low-wavenumber side and the high-wavenumber side, respectively. The spectroscopic elements <NUM> and <NUM> are situated to disperse light collected by the light collecting unit <NUM> through imaging lenses <NUM> and <NUM> and to project a continuous spectrum to the imaging unit <NUM> along a row or column direction of a light detection element array of the imaging unit <NUM>.

The optical spectrum 280sl of low wavenumbers and the optical spectrum 280sh of high wavenumbers are projected to the imaging unit <NUM> along light detection elements <NUM> arrayed in the row direction 172r, according to the present exemplary embodiment as illustrated in <FIG> and <FIG>. In other words, the optical spectrum 280sl of low wavenumbers and the optical spectrum 280sh of high wavenumbers are projected to the imaging unit <NUM> along the row direction 172r discontinuously with a non-projection band NPB between row-direction element numbers <NUM> and <NUM> as illustrated in <FIG>. The non-projection band NPB is set correspondingly to a silent region of <NUM>-<NUM> to <NUM>-<NUM>. The non-projection band NPB is also referred to as "non-projection band" or "non-projection wavenumber range".

The non-projection band NPB is desirably set to a wavenumber range of <NUM>-<NUM> or higher, more desirably a wavenumber range of <NUM>-<NUM> or higher.

According to the present exemplary embodiment, an optical spectrum of high wavenumbers from <NUM>-<NUM> to <NUM>-<NUM> and an optical spectrum of low wavenumbers from <NUM>-<NUM> to <NUM>-<NUM> in the <NUM>-cm-<NUM> wavenumber range of received light from <NUM>-<NUM> to <NUM>-<NUM> excluding the non-projection band NPB of <NUM>-<NUM> are projected to the imaging unit <NUM>. Thus, a wavenumber width that can be divided by a single light detection element according to the present exemplary embodiment is reduced to <NUM>/<NUM> at the low wavenumbers and <NUM>/<NUM> at the high wavenumbers compared to projections illustrated in <FIG> and <FIG> according to a conventional technique, and the spectral resolution in the wavenumber direction is improved. The optical spectrum of the low wavenumbers ranging from <NUM>-<NUM> to <NUM>-<NUM> and the optical spectrum of the high wavenumbers ranging from <NUM>-<NUM> to <NUM>-<NUM> are projected discontinuously from each other by arranging the spectroscopic element <NUM> for the low wavenumbers and the spectroscopic element <NUM> for the high wavenumbers are shifted in the row direction 172r of the imaging unit <NUM>. In other words, the spectroscopic element <NUM> for low wavenumbers and the spectroscopic element <NUM> for high wavenumbers respectively project the plurality of optical spectra 280sl and 280sh having a different wavenumber range from each other to a plurality of regions of the imaging unit <NUM>. In other words, the plurality of optical spectra 280sl and 280sh having a different wavenumber range from each other is projected to a plurality of regions of the imaging unit <NUM> with the non-projection band NPB, which is not projected to the imaging unit <NUM>, between the optical spectra 280sl and 280sh.

According to a modified example of the present exemplary embodiment, exit ends of optical fibers <NUM> and <NUM> are arranged in parallel and shifted vertically on the sheet plane of <FIG> with respect to one of the spectroscopic elements <NUM> and <NUM>. With the configuration according to the modified example, optical spectra of low and high wavelengths are discontinuously projected to the imaging unit <NUM> along the row direction 172r from the one of the spectroscopic elements <NUM> and <NUM>. With the configuration according to the modified example, the other one of the spectroscopic elements <NUM> and <NUM>, the corresponding imaging lens <NUM> or <NUM>, the other one of the band-pass filters <NUM> and <NUM>, and the branch portion <NUM> can be omitted.

The spectroscopic elements <NUM> and <NUM> do not have to be the same spectroscopic element, and each can be optimized as needed based on a lattice period and a wavenumber band of a central wavelength to be projected in order to project spectral images of low and high wavelengths to a wide region on the imaging unit <NUM>. In this case, the imaging unit <NUM> is situated at an optimum position in line with an individual emission angle of the spectroscopic elements <NUM> and <NUM> considering diffraction efficiency and wavenumber resolution.

The imaging unit <NUM> employs an imaging device, such as a charge-coupled device (CCD) image sensor or a complementary metal oxide semiconductor (CMOS) image sensor, with light detection elements arranged two-dimensionally. The plurality of light detection elements <NUM> of the imaging unit <NUM> according to the present exemplary embodiment is arranged in a matrix. In a case where the plurality of light detection elements <NUM> is arranged in a delta array, however, row and column directions are associated with two of three axes or are associated with a direction of one of the three axes and a combined direction of a combination of the remaining two axes. The identification apparatus <NUM> identifies properties of the sample 900i while the conveyance unit <NUM> conveys the sample 900i, and the discrimination apparatus <NUM> discriminates the sample 900i based on the identification result. Thus, it is desirable to increase the conveyance velocity vc of the conveyance unit <NUM> in order to increase the throughput of the sorting processing by the identification apparatus <NUM>. The optical spectra 280sl and 280sh projected onto the imaging unit <NUM> are based on Raman scattered light generated from the sample 900i moving on the conveyance surface <NUM>. Thus, the optical spectra 280sl and 280sh are projected onto the imaging unit <NUM> while the conveyed sample 900i is in the irradiation region of the irradiation light <NUM> (the converged light <NUM>) emitted from the irradiation unit <NUM>. For example, in a case where the conveyance velocity vc of the conveyance unit <NUM> is <NUM>/second and the length of the sample 900i in the conveyance direction dc is <NUM>, the time during which the imaging unit <NUM> can detect a spectral image formed by Raman scattered light from the sample 900i is <NUM> milliseconds or less. The imaging unit <NUM> is therefore required to have a high frame rate. An imaging unit with a high frame rate is a CMOS image sensor, and therefore the imaging unit <NUM> is desirably a CMOS image sensor.

As described above, the intensity of Raman scattered light from the sample 900i is significantly low, so that the intensity of incident light on each element of the light detection elements <NUM> of the imaging unit <NUM> is also significantly low. It is therefore desirable to use an imaging unit with high sensitivity to the wavenumber region where spectral images corresponding to the optical spectra 280sl and 280sh are acquired, as the imaging unit <NUM>. In general, a rolling shutter image sensor has a simpler pixel structure and a higher aperture ratio than a global shutter image sensor, and photoelectric conversion elements can be enlarged, so that the sensitivity and the dynamic range can be increased. Furthermore, having a simple pixel structure, a rolling shutter image sensor has an advantage that the cost is lower than a global shutter image sensor. For the foregoing reasons, a rolling shutter CMOS image sensor is used as the imaging unit <NUM> according to the present exemplary embodiment.

The imaging unit <NUM> can employ a rolling reset type image sensor that sequentially resets each row of the array of the light detection elements <NUM>. This increases the exposure time of each row of the array of the light detection elements <NUM> as long as possible, and the sensitivity increases.

The imaging unit <NUM> according to present exemplary embodiment includes a crop reading function of reading a specific row in a light receiving unit <NUM> including the light detection elements <NUM> arrayed two-dimensionally in the row direction 172r and a column direction 172c. Thus, in a case where a morphologic information acquisition unit <NUM> described below detects an arrival of the sample 900i at a light collectable region of the light collecting unit <NUM>, the imaging unit <NUM> reads a specific row in the light receiving unit <NUM> corresponding to the light collecting unit <NUM>.

The imaging unit <NUM> includes a reading circuit <NUM>, a horizontal scan circuit <NUM>, a vertical scan circuit <NUM>, and an output circuit <NUM>. The imaging unit <NUM> sequentially reads signals from a plurality of pixels arranged in a matrix shape row by row. The vertical scan circuit <NUM> selects a row in the light receiving unit <NUM> and drives the selected row. The reading circuit <NUM> reads signals output from the pixels of the row selected by the vertical scan circuit <NUM> and transfers the read signals to the output circuit <NUM> based on control by the horizontal scan circuit <NUM>. This is how the reading in a main-scan direction (row direction) is performed. The row selected by the vertical scan circuit <NUM> is shifted, and the reading circuit <NUM> performs reading in the main-scan direction based on control by the horizontal scan circuit <NUM>. The foregoing operations are repeated so that the selected row is shifted in a sub-scan direction (column direction), and thereby signals from the entire light receiving unit <NUM> are read. The read signals are output as output signals to a material information reference unit <NUM> through an output terminal <NUM> of the output circuit <NUM>. The material information reference unit <NUM> is situated outside the imaging unit <NUM>. At this time, the scanning in the main-scan direction is performed at high speed, and the scanning in the sub-scan direction is slower than the scanning in the main-scan direction.

The imaging lenses <NUM> and <NUM> changes, into parallel light, branch light transmitted through the optical fiber <NUM> from the light collecting unit <NUM> and through one of the optical fibers <NUM> and <NUM> from the branch portion <NUM>. The optical fibers <NUM> and <NUM> are also referred to as branch light guide portions <NUM> and <NUM>. The band-pass filters <NUM> and <NUM> reduce the intensity of excitation light components contained in the collected light and transmit a portion of Raman scattered light components. The band-pass filters <NUM> and <NUM> have spectral transmission characteristics to attenuate Raman scattered light of high wavenumbers and Raman scattered light of low wavenumbers, respectively. The spectroscopic elements <NUM> and <NUM> disperse collected light to spread wavelength components in a fan-shaped form. The imaging lenses <NUM> and <NUM> project the light dispersed by the spectroscopic elements <NUM> and <NUM> onto the imaging unit <NUM>. The spectroscopic elements <NUM> and <NUM> are transmissive diffractive gratings. Reflective diffractive gratings can also be used as the diffractive gratings. In this case, a spectroscopic element configuration employs a Rowland arrangement or a Czerny-Turner configuration. The spectroscopic elements <NUM> and <NUM> are also referred to as diffractive gratings <NUM> and <NUM>.

The imaging unit <NUM> acquires spectral information Si about the sample 900i considering a captured spectral image, photoelectric conversion characteristics of an image sensor of the imaging unit <NUM>, and transmission characteristics of an optical system. In addition, the spectroscopic elements <NUM> and <NUM> can also acquire polarization information including circular dichroism and optical rotatory dispersion together with optical spectra.

The spectral information acquisition unit <NUM> includes the material information reference unit <NUM>, which acquires material information about the sample 900i based on the spectral information Si acquired by the spectral image acquisition unit <NUM>. The material information reference unit <NUM> refers to a material database (not illustrated) storing Raman scattered light reference data and acquires material information Mi based on the similarity between the spectral information Si and reference data. The material information Mi identifies materials contained in the sample 900i. The spectral information acquisition unit <NUM> stores at least one of the spectral information Si and the material information Mi in a first storage unit <NUM> via an instruction unit <NUM> described below.

The material database that the material information reference unit <NUM> refers to can be stored on a local server of the identification apparatus <NUM> or on a remote server that is accessible via the Internet or an intranet.

As described above, the spectral information acquisition unit <NUM> acquires the material information Mi about mixtures of, for example, materials, additives, and impurity components contained in the sample 900i.

The morphologic information acquisition unit <NUM> includes a camera <NUM> and an image processing unit <NUM>, as illustrated in <FIG>, and acquires morphologic information Fi about the sample 900i. The camera <NUM> is situated such that an imaging field of view <NUM> overlaps the conveyance unit <NUM>. The image processing unit <NUM> processes an image of a sample captured by the camera <NUM>. Similarly to the material information Mi, the morphologic information Fi is information about properties of the sample 900i.

The image processing unit <NUM> performs image processing including contrast and contour extraction, and acquires, for example, the length of each sample 900i in the conveyance direction dc, and the reflected color of each sample 900i, the shape of each sample 900i, and the mixing level of materials of each sample 900i. The image processing unit <NUM> is also referred to as an element that performs processing to acquire size information about each sample 900i. The morphologic information acquisition unit <NUM> can include a photo-interrupter (not illustrated) and a laser interferometer (not illustrated) in place of the camera <NUM>. The morphologic information acquisition unit <NUM> is also referred to as an imaging unit. The morphologic information acquisition unit <NUM> is also an element selectively employed in the identification apparatus <NUM>.

The acquisition unit <NUM> acquires identification information Di about whether the sample 900i is a target sample or a non-target sample based on the material information Mi or the spectral information Si acquired by the spectral information acquisition unit <NUM> and the morphologic information Fi acquired by the morphologic information acquisition unit <NUM> as illustrated in <FIG>. The acquisition unit <NUM> acquires the identification information Di for each sample 900i. The acquisition unit <NUM> outputs the acquired identification information Di to the instruction unit <NUM>.

In other words, the acquisition unit <NUM> identifies properties of the sample 900i based on a Raman spectrum contained in the secondary light of the light collected by the light collecting unit <NUM>. In other words, the acquisition unit <NUM> according to the present exemplary embodiment identifies properties of each sample 900i based on the image of the sample acquired from the camera <NUM> and the Raman spectrum contained in the secondary light of the light collected by the light collecting unit <NUM>.

The spectral information acquisition unit <NUM> and the morphologic information acquisition unit <NUM> according to the present exemplary embodiment can be replaced with a hyperspectral camera or a multiband camera capable of acquiring the morphologic information Fi and the spectral information Si from a captured image, according to a modified form. Specifically, an identification apparatus (not illustrated) according to the modified form includes a detection system that acquires multi-dimensional data from which material information and morphologic information are readable.

The identification apparatus <NUM> includes a control unit <NUM> including the instruction unit <NUM>, a second storage unit <NUM>, and the first storage unit <NUM>. The instruction unit <NUM> controls the discrimination operation of the discrimination apparatus <NUM> based on the properties of each sample 900i. The second storage unit <NUM> stores a control condition of the discrimination operation. The first storage unit <NUM> stores the properties of each sample 900i. The control unit <NUM> includes a display unit <NUM> configured to provide a graphical user interface (GUI) via which a user can designate the control condition. The display unit <NUM> may display information acquired by the acquisition unit <NUM>.

The first storage unit <NUM> is configured to store, for each sample 900i, the identification information Di, the material information Mi, the spectral information Si, and the morphologic information Fi in association with a timing tp of the passing of the sample 900i through the irradiation light <NUM>.

On the other hand, the second storage unit <NUM> is configured to store a control condition for controlling an intensity Is of the discrimination operation of the discrimination apparatus <NUM> that corresponds to the identification information Di for each sample 900i. Forms of the control condition include a table for reference, an algebraically-expressed general formula, and machine-learned statistical information.

The instruction unit <NUM> estimates the time of the passing of the sample 900i through a processing region where the discrimination apparatus <NUM> performs discrimination processing on the sample 900i based on the materials and size of each sample 900i based on the identification information Di from the acquisition unit <NUM>, and generates an instruction to control the discrimination operation of the discrimination apparatus <NUM>. The time of the passing of the sample 900i through the processing region can be estimated based on at least one of a signal from the morphologic information acquisition unit <NUM>, a signal from the spectral information acquisition unit <NUM>, and a signal from a sample sensor (not illustrated) of the conveyance unit <NUM>.

The discrimination apparatus <NUM> includes an air nozzle <NUM> and a discrimination control unit <NUM> as illustrated in <FIG>. The air nozzle <NUM> discharges compressed air for a predetermined discharge time, at a predetermined discharge velocity, and at a predetermined discharge flow rate. The discrimination control unit <NUM> controls a solenoid valve (not illustrated) of the air nozzle <NUM>. The discrimination control unit <NUM> receives a control signal from the instruction unit <NUM> of the identification apparatus <NUM>. The discrimination operation of the discrimination apparatus <NUM> according to the present exemplary embodiment includes an operation of discharging a fluid. The fluid to be discharged by the discharge operation includes air, dry nitrogen, inert gas such as a noble gas, liquid, and gas-liquid mixture fluid (aerosol). The discrimination apparatus <NUM> collects the sample 900i into a target collection basket <NUM> and a non-target collection basket <NUM> or <NUM> according to the properties of the sample 900i based on the control signal from the instruction unit <NUM>.

A discharge apparatus of the discrimination apparatus <NUM> that discharges a fluid can be replaced with a flap gate that opens and closes at a predetermined angular velocity or a shutter that opens and closes at a predetermined velocity. The morphologic information acquisition unit <NUM>, the spectral information acquisition unit <NUM>, the discrimination apparatus <NUM>, and components thereof included in the identification apparatus <NUM> are situated in parallel at different positions in the conveyance width direction dw of the conveyance unit <NUM> for system consolidation and high-speed processing. The discrimination apparatus <NUM> can be considered as an element of the identification apparatus <NUM> and is sometimes referred to as a discrimination unit <NUM>.

The conveyance unit <NUM> is a conveyance unit that conveys the plurality of samples 900i (i = <NUM>, <NUM>,. ) fed sequentially from the feeder <NUM> at the predetermined conveyance velocity vc in the conveyance direction dc (the x-direction illustrated in <FIG>). The conveyance unit <NUM> and the feeder <NUM> form a conveyance unit that conveys the sample 900i.

The conveyance unit <NUM> according to the present exemplary embodiment includes the conveyer belt that conveys the sample 900i fed from the feeder <NUM> in the conveyance direction dc at the velocity vc linearly on the conveyance surface <NUM>. The conveyance unit <NUM> can be replaced with a turntable feeder that externally conveys a sample spirally, a vibrating feeder equipped with a vibration generator that moves a sample in a predetermined direction, or a conveyer roller including a plurality of rollers, according to a modified example.

The conveyance unit <NUM> moves the sample 900i such that the sample 900i passes through the imaging field of view <NUM> of the camera <NUM>. Thus, the conveyance unit <NUM> is also referred to as a placement portion <NUM> with respect to the morphologic information acquisition unit <NUM>. Similarly, the conveyance unit <NUM> moves the sample 900i such that the sample 900i passes through an effective light collection region (not illustrated) of the light collecting unit <NUM>. Thus, the conveyance unit <NUM> is also referred to as the placement portion <NUM> with respect to the light collecting unit <NUM>.

According to the present exemplary embodiment, the conveyance velocity vc of the conveyance unit <NUM> that is <NUM>/s to <NUM>/s is applicable in a case of the conveyer belt.

Further, a case where the classifying processing for filtering the shape and size of the sample 900i is performed as the preprocessing of the feeding by the feeder <NUM> is also a modified form of the identification method using the identification apparatus <NUM> according to the present exemplary embodiment. A vibrating conveyer, a vibrating sieving machine, or a crushed grain checking machine is used as a unit that performs preprocessing.

An identification apparatus according to a second exemplary embodiment will now be described with reference to <FIG> is a diagram illustrating a relationship between the light detection element numbers of light detection elements arrayed in the row direction 172r of the imaging unit <NUM> according to the present exemplary embodiment and the wavenumbers of optical spectra projected in the row direction 172r.

The identification apparatus according to the present exemplary embodiment is different from the identification apparatus <NUM> according to the first exemplary embodiment in that the optical spectra 280sl and 280sh are projected to different positions on the imaging unit <NUM> in the row direction 172r and the column direction 172c as illustrated in <FIG>. Specifically, the present exemplary embodiment and the first exemplary embodiment are different in the directions of discontinuous projections of the optical spectra 280sl and 280sh to the imaging unit <NUM>.

The identification apparatus according to the present exemplary embodiment is similar to the first exemplary embodiment in that the spectral image acquisition unit <NUM> includes two sets of spectroscopic elements <NUM> and <NUM> with respect to one imaging unit <NUM>, whereas the present exemplary embodiment is different from the first exemplary embodiment in the arrangement of the spectroscopic elements <NUM> and <NUM> with respect to the imaging unit <NUM>. According to the first exemplary embodiment, the spectroscopic elements <NUM> and <NUM> are shifted in the row direction 172r. According to the second exemplary embodiment, the spectroscopic elements <NUM> and <NUM> are shifted in the column direction 172c (not illustrated).

According to the present exemplary embodiment, the optical spectrum 280sl of low wavenumbers and the optical spectrum 280sh of high wavenumbers are projected to the light receiving unit <NUM> of the imaging unit <NUM> along the light detection elements <NUM> arrayed in the row direction 172r as illustrated in <FIG>. The optical spectrum 280sl of low wavenumbers and the optical spectrum 280sh of high wavenumbers are projected to the imaging unit <NUM> with the non-projection band NPB between the optical spectra 280sl and 280sh in the column direction 172c as illustrated in <FIG>. The optical spectrum 280sl of low wavenumbers and the optical spectrum 280sh of high wavenumbers are projected correspondingly to the light detection elements <NUM> corresponding to element numbers <NUM> to <NUM> along the row direction 172r. The non-projection band NPB is set correspondingly to the silent region of <NUM>-<NUM> to <NUM>-<NUM> as described in the first exemplary embodiment.

According to the present exemplary embodiment, the optical spectra 280sl and 280sh of the low-wavenumber band of <NUM>-<NUM> to <NUM>-<NUM> and the high-wavenumber band of <NUM>-<NUM> to <NUM>-<NUM> excluding the non-projection band NPB of <NUM>-<NUM> are shifted in the column direction 172c and projected to the imaging unit <NUM>. Thus, a wavenumber width that can be divided by a single light detection element according to the present exemplary embodiment is reduced to <NUM>/<NUM> at the low wavenumbers and <NUM>/<NUM> at the high wavenumbers compared to projections illustrated in <FIG> and <FIG> according to a conventional technique, and the spectral resolution in the wavenumber direction is improved.

An identification apparatus according to a third exemplary embodiment will now be described with reference to <FIG> is a diagram illustrating the conveyance unit <NUM> and a plurality of conveyance tracks TR-p (p = <NUM> to <NUM>) that are a main portion according to the third exemplary embodiment. <FIG> corresponds to a diagram illustrating a projection of a light collecting optical system and a discrimination apparatus of an identification apparatus <NUM> to a plane A-A' illustrated in <FIG> as a projection plane. A cross section B-B' in <FIG> corresponds to the schematic configuration diagram illustrated in <FIG>.

The identification apparatus <NUM> illustrated in <FIG> is different from the identification apparatus <NUM> illustrated in <FIG> in that four imaging fields <NUM>-p of the camera <NUM>, four irradiation spots from the irradiation unit <NUM>-p, and four air nozzles <NUM>-p of the discrimination apparatus <NUM> are arranged in the conveyance width direction dw. The identification apparatus <NUM> is a multi-column identification apparatus including a plurality of units for identification arranged in parallel at different positions in the conveyance width direction dw intersecting with the conveyance direction dc. The identification apparatus <NUM> realizes system consolidation and high-speed identification processing compared to those of the identification apparatus <NUM>.

The identification apparatus <NUM> includes four conveyance tracks TRp (p = <NUM> to <NUM>) defined by feeding regions <NUM>-p (p = <NUM> to <NUM>) from the feeder <NUM>. The identification apparatus <NUM> includes the imaging fields <NUM>-p, irradiation spots <NUM>-p of the primary light, and air nozzles <NUM>-p arranged in series correspondingly to the respective tracks TRp.

In forming a multi-row identification apparatus, elements to be situated at different positions in the conveyance width direction dw of the conveyance unit <NUM> can be situated independently or can be arrayed. The identification apparatus <NUM> includes a feeder 500A and a multi-discrimination apparatus (not illustrated). An air supply port of the feeder 500A is arrayed. The air nozzles <NUM>-p of the multi-discrimination apparatus are a multi-nozzle.

According to the present exemplary embodiment, light collected (by a light collecting unit provided for each track- not shown) from the irradiation spot <NUM>-p of the primary light corresponding to the conveyance track TRp (p = <NUM> to <NUM>) is guided to an optical fiber (light guide portion) (not illustrated) and a spectroscopic element set <NUM>-p including a spectroscopic elements <NUM>-p and <NUM>-p. The spectroscopic elements <NUM>-p and <NUM>-p are shared by the plurality of conveyance tracks TRp (p = <NUM> to <NUM>), and thus the identification apparatus <NUM> includes one for each. In contrast, the light collecting optical system includes four low-wavenumber band-pass filters, four high-wavenumber band-pass filters, four low-wavenumber imaging lenses, four high-wavenumber imaging lenses, four low-wavenumber optical fibers, and four high-wavenumber optical fibers correspondingly to the number of rows p, which is four. Respective exit ends of the plurality of low-wavenumber optical fibers and the high-wavenumber optical fibers according to the present exemplary embodiment are arrayed at predetermined intervals in one line in the vertical direction of <FIG> to form a one-dimensional exit end array. The exit end array with the exit ends arrayed in the vertical direction of <FIG> is situated in front of each of the imaging lenses <NUM> and <NUM>, and thereby optical spectra 280slp and 280slh corresponding to the conveyance track TRp are projected with a space in the column direction 172c. The spectroscopic elements <NUM>-p and <NUM>-p are shifted along the row direction 172r and projected in the imaging unit <NUM> as described in the first exemplary embodiment. The low-wavenumber band of <NUM>-<NUM> to <NUM>-<NUM> and the high-wavenumber band of <NUM>-<NUM> to <NUM>-<NUM> that are respectively projected from the spectroscopic elements <NUM>-p and <NUM>-p are discontinuously projected to the imaging unit <NUM> with the non-projection band NPB therebetween as described in the first exemplary embodiment.

A wavenumber width that can be divided by a single light detection element according to the present exemplary embodiment is therefore reduced to <NUM>/<NUM> at the low wavenumbers and <NUM>/<NUM> at the high wavenumbers compared to the conventional technique illustrated in <FIG> and <FIG>, similarly to the first exemplary embodiment. According to the present exemplary embodiment, the spectral resolution of optical spectra 280sl1 to 280sl4 of low wavenumbers and optical spectra 280sh1 to 280sh4 of high wavenumbers in the wavenumber direction is improved compared to the conventional technique illustrated in <FIG> and <FIG>, similarly to the first exemplary embodiment. According to a modified form, one of the exit end arrays according to the present exemplary embodiment can be juxtaposed with one spectroscopic element in the vertical direction of <FIG> as described in the first exemplary embodiment. According to the modified form, one spectroscopic element can discontinuously project the optical spectra 280slp and 280shp in the row direction 172r. According to the modified form, the exit ends can be arranged in the vertical direction of <FIG> to form a two-dimensional array. In the present specification, the term "optical spectrum" refers to an intensity distribution of diffraction light projected in the fan-shaped form from the spectroscopic element for each wavenumber, and the term "optical spectrum" may be used to also refer to a spatial spread of diffraction light and a spectral image captured by the imaging unit.

The present invention provides an identification apparatus including a spectroscopic element as set out in the appended set of claims, situated to effectively disperse collected light and an imaging unit. In other words, the present invention provides an identification apparatus that ensures a spectral resolution of a wavenumber band useful in identifying properties of a sample.

Claim 1:
An identification apparatus comprising:
irradiation means (<NUM>) configured to irradiate at least one sample (900i) with light;
light collecting means (<NUM>) for collecting scattered light from the at least one sample (900i);
a plurality of spectroscopic elements (<NUM>, <NUM>) configured to disperse light from the light collecting means (<NUM>);
imaging means (<NUM>) that includes a plurality of light detection elements (<NUM>) arrayed in a row direction (172r) and a column direction (172c) and to which Raman spectra from the plurality of spectroscopic elements (<NUM>, <NUM>) are projected, whereby the plurality of spectroscopic elements disperse the light collected by the collecting means along the row direction (172r); and
acquisition means (<NUM>) for acquiring spectral information about the at least one sample (900i) based on an output signal from the imaging means (<NUM>), whereby the plurality of spectroscopic elements are arranged to project respective Raman spectra corresponding to the at least one sample (900i) to the imaging means (<NUM>) in such a way that an intermediate Raman spectral band is not projected in at least one of the row direction (172r) or the column direction (172c).