Identification device, identification method, and article manufacturing method

Abstract

To provide an identification device which achieves both of high S / N and high throughput.SOLUTION: An identification device for identifying a type of an object comprises: an illumination unit which illuminates the object; a sensor which measures reflection light from the illuminated object; and a processing unit which identifies the type of the object on the basis of the measurement result by the sensor. The illumination unit comprises: a scan part which scans illumination light that illuminates the object; and a control part which controls the scan part. The control part controls the scan part on the basis of the position of the object such that the illumination light tracks the moving object and the position of the illumination light on the surface of the object is changed.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an identification device for identifying the type of an object. [Background technology]

[0002] Traditionally, resin molded parts have been widely used for structural and exterior parts of automobiles and electrical appliances from the viewpoint of mass production and part costs. In recent years, the industrial sector has been forced to consider the environment, and these resin molded parts are also being recycled and reused. In conventional recycling, scrapped automobiles and scrapped home appliances are crushed into pieces of about 10 to 100 mm in size after iron and aluminum are recovered through various recycling processes, and the pieces are collected as residues containing various types of plastics. Ultimately, they are often reused as thermal recycling, where they are burned as fuel.

[0003] Efforts are also being made to horizontally recycle these plastic residues, using them again as materials for resin molded parts, and resin identification devices are being developed that can identify and separate specific types of plastic from residues containing a variety of other plastics.

[0004] As a measurement method for identifying the type of resin in a non-contact manner by irradiating light, the following technique for identifying the type of resin by utilizing Raman scattering has been disclosed.

[0005] Patent Document 1 discloses a resin identification device that can obtain a strong Raman scattering signal without damaging or deteriorating the resin by translating the illumination light when measuring the resin flowing on a belt conveyer by Raman spectroscopy. During irradiation with excitation laser light, the light collection optical system is translated relative to the upper surface of the mounting table within a range equal to or larger than the spot diameter of the excitation laser light on the object, preferably within a range equal to or larger than two to three times the spot diameter. This prevents the excitation laser light from being concentrated on one point on the object, resulting in a resin identification device that does not damage or degrade the object. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2013-36971 A Summary of the Invention [Problem to be solved by the invention]

[0007] In Patent Document 1, it is possible to identify the type of resin by Raman measurement without denaturing the resin even when irradiated with a high-power laser. Generally, it is necessary to measure a very weak signal in Raman measurement, and a high-power laser light source is required to configure an identification device. However, when considering an inexpensive LD that can be mounted on the device as a light source, since the LD output is limited, it is necessary to improve the S / N ratio. In order to obtain a Raman signal with a high S / N ratio, for example, the belt speed is slowed down, the exposure time of the sensor is lengthened to increase the signal strength, and the noise is reduced by repeated averaging for measurement.

[0008] On the other hand, since the resin residue is generated in the recycling process in large quantities, at 1t / h or 2t / h, it is required to increase the throughput of the identification process, and it is desirable to increase the speed of the belt conveyor.If the speed of the belt conveyor is increased in order to meet the requirement of throughput, the time that the sample is present directly under the illumination light becomes shorter, so it is not possible to ensure the exposure time of the spectrometer for Raman measurement, or the number of repeated averages cannot be ensured, making it difficult to ensure the S / N ratio.

[0009] As described above, it is difficult to achieve both a high S / N ratio and high throughput when selecting resins.

[0010] Therefore, an object of the present invention is to provide an identification device that achieves both a high S / N ratio and high throughput. [Means for solving the problem]

[0011] An identification device as one aspect of the present invention that solves the above-mentioned problems is an identification device that identifies the type of object, and includes an illumination unit that illuminates the object, a sensor that measures reflected light from the illuminated object, and a processing unit that identifies the type of the object based on the measurement results by the sensor, wherein the illumination unit includes a scanning unit that scans the illumination light that illuminates the object, and a control unit that controls the scanning unit, and the control unit controls the scanning unit based on the position of the object so that the illumination light follows the moving object and changes the position of the illumination light on the surface of the object. Effect of the Invention

[0012] According to the present invention, it is possible to provide an identification device that achieves both a high S / N ratio and high throughput. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 illustrates a sorting system. [Diagram 2] FIG. 2 is a diagram showing details of a measuring unit 30. [Diagram 3] FIG. 1 is a diagram showing how illumination light is scanned by a galvanometer scanner. [Figure 4] 1 is a diagram showing how illumination light is scanned in a scanning area 400. FIG. [Diagram 5] FIG. 13 is a diagram showing a scanning trajectory when measuring multiple samples within a scanning region. [Figure 6] FIG. 13 is a diagram showing how a sample outside the scanning region is measured. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0015] 1 is a diagram showing the configuration of a sorting system. The sorting system of this embodiment has a belt conveyor 1 (moving unit) that moves samples (objects), performs an identification process to identify the type of sample transported by the belt conveyor 1, and sorts the samples according to the identification results.

[0016] Samples 10 and 11 are metal pieces mainly containing metal, ceramic pieces mainly containing metal oxide crystals, glass pieces containing amorphous metal oxides, resin pieces mainly containing resin, etc. In many cases, samples 10 and 11 are industrial waste such as waste electrical appliances and automobiles that have been crushed into flat sizes of about 10 to 100 mm after undergoing a crushing process as a pre-process in recycling.

[0017] In this specification, the term "resin" refers to organic polymers in general, including thermoplastic resins (plastics), thermosetting resins, rubber, elastomers, cellulose, paper, and the like.

[0018] In addition, Samples 10 and 11 may contain various additives such as fillers such as glass or fiber, flame retardants, and plasticizers.

[0019] The sorting system according to this embodiment not only identifies the type of resin that constitutes the resin pieces, i.e., the material type (material quality, color, etc.) of the resin pieces, but also identifies the presence and type of these additives.

[0020] In the sorting device of this embodiment, samples to be sorted are fed onto the belt conveyor 1 by a fixed quantity feeder or a vibrating feeder (not shown) or the like, and the samples flow on the belt conveyor 1. On the belt conveyor 1, from the upstream side of the flow of the belt conveyor, a recognition unit 2 (measurement unit), a measurement unit 3, and a sorting unit 162 are arranged. After passing under the recognition unit 2 and the measurement unit 3, the sample 10 is projected from the belt conveyor 1 and passes in front of the sorting unit 162.

[0021] The recognition unit 2 performs image processing of a two-dimensional image including a sample, which is acquired by, for example, an area camera capable of acquiring two-dimensional images all at once, or a line camera capable of reconstructing a two-dimensional image. For example, the recognition unit 2 calculates the coordinates of the position where the sample 10 exists at time t0 as p1(x1, y1) from the information on the shape and size of the sample as a result of the image processing.

[0022] 3, the measurement unit 3 has a galvanometer scanner 41 and a galvanometer scanner 42 (scanning unit) that scan the illumination light 50, and an optical spectroscopic unit 30 that measures Raman scattered light (reflected light) from the sample. By controlling the scanning unit to tilt the principal ray of the illumination light 50, the illumination light is tilted as in 50a or 50b with respect to the measurement unit 3, making it possible to move the illumination light (measurement point).

[0023] As shown in FIG. 2, the optical spectroscopic section 30 has a light source 301 and a lens 302 (illumination section). The optical spectroscopic unit 30 irradiates a mirror configured in a galvano scanner with laser light from a light source 301 as illumination light 50 via lenses 302 and 304. A dichroic mirror 303 is disposed between the lenses 302 and 304, and is configured to transmit light of the wavelength λ of the light source 301.

[0024] The processing unit 140 has a control unit that controls the galvano scanner. The processing unit 140 calculates the position coordinate p1 (x1, y1+V(t1-t0)) of the moving sample at time t1 from the speed V of the belt conveyor 1, which is adjusted or measured in advance, and the time t0 at which the recognition unit 2 recognizes the sample. Then, the processing unit 140 outputs a control command to the galvano scanner so that the illumination light 50 illuminates the sample 10 at the time when the sample 10 reaches the scanning area 400 where the galvano scanners 41 and 42 can scan the illumination light 50. Then, the processing unit 140 controls the galvano scanner so that the illumination light 50 follows the moving sample 10. By using the two scanners, the galvano scanner 41 and 42, the illumination light can be scanned in the y-axis direction, which is the moving direction of the belt conveyor 1 (sample), and in the x-axis direction, which is perpendicular to the y-axis.

[0025] Specifically, as shown in Fig. 4, when the sample 10 reaches the upstream boundary of the movement of the belt conveyor 1 in the scanning area 400 (10a), the illumination light is scanned at the position of the illumination light 50a, and measurement is started. The sample 10 is illuminated so as to trace a trajectory 60 on the sample as it moves at a speed V in accordance with the movement of the belt conveyor 1, and Raman measurement is performed. Then, the measurement is completed when the sample 10 reaches the downstream boundary of the belt conveyor 1 in the scanning area 400 (10b). Here, the trajectory from the illumination light 50a to 50b indicates the average position of the scanning illumination light 50.

[0026] The size of the scanning area 400 in the belt movement direction is defined as B. The position of the illumination light 50 changes in the same direction as the belt movement direction, and illuminates the sample 10 for a time T=B / V so that the illumination light follows the sample 10, and illuminates the sample 10 without remaining at one point on the surface of the sample 10 during illumination.

[0027] Therefore, the energy of the illumination light is not concentrated on one point of the sample, and Raman measurement can be performed without denaturing the resin. Moreover, since the speed of the belt conveyor can be increased, even if a large amount of samples are flowed on the belt conveyor to increase the throughput of identification, the samples can be arranged in a spatially separated state.

[0028] In the case of a conventional method in which the illumination light 50 is not scanned, the size of the sample 10 in the belt movement direction is a, and the illumination light is irradiated for a time period of t=a / V.

[0029] As an example, we will describe a case where the speed of the belt conveyor is 1 m / s, the size of sample 10 is 10 mm, which is assumed to be the smallest size of a sample in the recycling process, and the scan area of ​​B is 200 mm.

[0030] In the conventional method with a fixed illumination light, the time t during which illumination light can be applied is 10 ms, whereas when the illumination light 50 is scanned and measured while tracking the sample, the measurement time is approximately 200 ms. Therefore, for black resins with a low amount of reflected light, the S / N ratio of weak Raman signals can be improved by extending the exposure time or averaging 20 pieces of data acquired with an exposure time of 10 ms.

[0031] On the other hand, in this embodiment, the illumination light 50 draws a zigzag trajectory like trajectory 60 so that the illumination light does not stay in one place while measuring the sample 10. Therefore, the energy of the illumination light is not dispersed over a wide area of ​​the sample 10, and the resin is not denatured during the measurement.

[0032] In the optical spectroscopic section 30, as described above, the illumination light 50 is reflected by the mirror portions 41m and 42m of the galvano scanner 41 and the galvano scanner 42, and then irradiated onto the sample. After being reflected by the sample, the Raman scattering is isotropically reflected and is reflected again by the mirrors 41m and 42m of the galvano scanner, and the Raman scattered light returns to the optical spectroscopic section 30. The Raman scattered light undergoes a Raman shift according to the substance of the material of the sample. Therefore, this time it is reflected by the dichroic mirror 303, and only the components that have undergone Raman scattering are transmitted by the bandpass filter 305 as an excitation light cut filter, and then it is dispersed by the spectroscopic element 306 (spectroscopic section). The light beam diffracted at different diffraction angles for each wavelength dispersed by the spectroscopic element 306 becomes a condensed light again by the lens 307, and the light for each wavelength that has undergone the Raman shift is received by the light receiving element configured in the sensor array 308. The signal output from the light receiving element is sent to the processing section 140 as a characteristic signal according to the substance of the sample, and is compared with a waveform specific to the material obtained by measuring a sample of a known material in advance, for example, to identify the material and the type of the sample.

[0033] Signals (measurement results) from the sensor array 308 are transmitted to the processing unit 140 at, for example, 300 fps. Measurement begins when the sample 10 reaches the interface on the upstream side of the belt movement in the scanning area 400 (10a), and the processing unit 140 extracts signals corresponding to the measurement from the group of signals transmitted from the sensor array 308 at 300 fps to identify the material. The method of extracting the corresponding signals may be determined, for example, based on the time when the operation command was issued.

[0034] If the sample type is identified by the processing unit 140 and the sample 10 is found to be a material to be sorted, an open signal is sent to the sorting unit 162 via the sorting controller 161 at time t2 when the sample 10 passes through the sorting unit 162. Then, air is ejected from a portion of the sorting unit 162 that is located at a position corresponding to the coordinate x1 of the sample 10 measured by the recognition unit 2, and the sample 10 is blown away by the air and collected in the collection box 72. If the sample 10 is not a material to be sorted, the sample 10 is projected from the belt conveyor 1 at a speed V and falls, and is collected in the collection box 71.

[0035] After completing the measurement of sample 10, the measurement unit 3 next measures sample 11, and thereafter measures samples (not shown) that flow one after another. The measurement unit 3 moves to the starting point for measuring sample 11 by rotating the galvanometer scanners 41 and 42 to change the inclination angle of the illumination light 50. Since the galvanometer scanner can scan the illumination light at high speed, the movement time until the next resin is measured is short, and samples that flow one after another can be measured. As a result, the measurement time is long and the Raman measurement has a high S / N ratio, and the number of samples to be measured is large, allowing resin sorting with high throughput.

[0036] In this embodiment, the recognition unit 2 is described as obtaining a two-dimensional image by an area sensor or a line camera, and determining the coordinates of the sample by image processing. However, this is not restrictive, and it is possible to adopt a method of recognizing an object from height information, such as a light cutting sensor. In addition, in this embodiment, a zigzag trajectory is used as the trajectory of the illumination light on the resin so that the illumination light does not stay at one point on the sample, but it goes without saying that the same effect can be obtained by drawing a circular motion, a spiral motion, a square, or the like, as long as the illumination light does not stay at the same point on the resin.

[0037] Furthermore, in the configuration of this embodiment, the recognition unit 2 acquires a two-dimensional image including the sample, and the two-dimensional image includes information on the brightness of the sample, i.e., the diffuse reflectance. According to the study by a person skilled in the art, the light intensity of Raman scattering is correlated with the diffuse reflectance, and the Raman scattered light from a white sample with high brightness is predominantly greater than the Raman scattered light from a black sample with low brightness. In other words, the measurement time required to obtain the same S / N ratio is shorter for a white sample than for a black sample.

[0038] From the above facts, it is effective to set the measurement time for the white resin to be shorter than that for the black resin in order to identify the samples more efficiently with the aim of improving throughput. In this case, as shown in Fig. 5, the illumination light is scanned for the black resin 10 under scanning conditions that measure along a trajectory 61 that moves over the entire area 400 from position 10a to position 10b.

[0039] On the other hand, the white resin is scanned with the illumination light under a scanning condition that the measurement time is, for example, 1 / 3 of that for the black resin. For example, the trajectory of the illumination light 50 is scanned as a step-like trajectory 62. This allows a plurality of samples 12, 13, and 14 with high brightness arranged side by side to be measured in total while moving from position 12a to 12b, from position 13a to 13b, and from position 14a to 14b. Of course, in this case, the trajectories 61 and 62 indicate the average position of the scanning illumination light 50, and it goes without saying that the average position of the illumination light 50 moves on each trajectory while simultaneously drawing a trajectory 60 on the resin. In this way, the processing unit has a control unit that controls the scanning unit to change the scanning condition of the illumination light based on the information of the object.

[0040] The flowing samples vary in size and color. As already mentioned, the higher the brightness of the sample, the stronger the Raman scattering intensity, and the lower the brightness, the weaker the Raman scattering light. In other words, the higher the brightness, the higher the reliability of identification to identify the resin type, and the lower the brightness, the lower the reliability of identification to identify the resin type. It goes without saying that the higher the purity of the desired type of resin to be recovered, the higher its utility value, but it is preferable to recover more resins with higher brightness, as this increases the reliability of the average identification and therefore the purity of the desired resin recovered.

[0041] On the other hand, since the samples flowing over the area 400 are actually randomly arranged on the belt conveyor 1, there is a certain probability that the density of the samples will be high, and it is assumed that there will not be enough time for the scanning of the illumination light 50 to measure all of the resin groups with high density in order. In this case, the processing unit 140 can issue a command to the galvano scanners 41 and 42 to skip the measurement of one of the samples. In other words, when multiple objects are present within the scannable range of the illumination light, the processing unit 140 determines the object to be measured based on the object information.

[0042] At this time, the purity of the finally collected samples can be improved by prioritizing measurement of samples with higher brightness based on the brightness information of each sample in the image obtained by the recognition unit 2. Furthermore, it is also effective to increase the amount of resin finally collected by prioritizing measurement of samples with larger sizes based on the shape information of the samples obtained by the recognition unit 2.

[0043] In this embodiment, the speed of the belt conveyor 1 is a previously measured or adjusted speed V, and the operation of tracking the illumination light in the measuring unit 3 and the sorting operation in the sorting unit 162 are configured to issue commands based on time. However, for example, a laser Doppler velocimeter or an image correlation type displacement meter that directly measures the belt speed can be arranged around the recognition unit 2 or the measuring unit 3, and the measured values ​​related to the belt movement amount from these measuring instruments can be input to the processing unit 140. This makes it possible to issue operation commands to the galvano scanners 41 and 42 based on the measured belt movement amount, and it is effective to perform more accurate illumination light tracking operation and sorting operation in the sorting unit 162 to increase the recovery amount. In this case, as a method of extracting signals when the sample is illuminated from the signal group transmitted from the sensor array 308, the measured values ​​related to the belt movement amount at the time each signal is generated can be used to determine the signal. This makes it possible to more accurately extract the signal when the illumination light 50 is staying on the resin.

[0044] Regarding signal extraction, it is also effective to measure a sample (specimen) showing a known specific feature (characteristic) that is not expected in normal measurement, such as a sample with high reflectivity that saturates the measurement, in advance just before moving to the measurement start point or before the specified time. For example, as shown in FIG. 6, a fluorescent sample 20 that emits a large amount of fluorescence and whose measured value saturates in the sensor array 308 is placed in a position outside the scanning area 400 and can be measured by the measurement unit 3. Then, an operation is performed to change the angle of the illumination light 50 to 50c so as to measure the fluorescent sample 20 just before scanning the position 10a where the sample 10 reaches the interface on the upstream side of the belt movement in the scanning area 400 or before the specified time. This makes it easier to extract measurement data in the processing unit 140 at the subsequent stage. The processing unit 140 may extract and process data immediately after the data where the level of each element is at the maximum value appears, or data after a specified number of data, as data to be used for determining the material of the sample, from the data continuously transferred from the sensor array 308.

[0045] Samples that show characteristic data are not limited to these, and can also be light traps that have very little reflected light, alloy resins that show the characteristics of multiple resins simultaneously, etc., as long as the sample shows known characteristics that are not expected in normal measurements.

[0046] As explained above, based on the resin information recognized by the recognition unit 2, the angle of the principal ray of the illumination light is changed by the scanning unit, for example a galvano scanner, and the illumination light is irradiated so that the average position follows the belt movement direction. Furthermore, by scanning the illumination light so that it does not stay at the same position on the resin during measurement, Raman spectroscopy is performed for point measurement while tracking the sample even at high belt speeds, so that resin identification by Raman spectroscopy can be performed with a high S / N ratio and high throughput.

Claims

1. 1. An identification device for identifying a type of object, comprising: A scanning unit that scans an illumination light that illuminates the object; A control unit that controls the scanning unit; a light receiving unit that receives light from the object illuminated by the illumination light, The control unit controls the scanning unit to illuminate the object based on information about a characteristic of the object.

2. The identification device according to claim 1 , wherein the control unit controls the scanning unit based on information relating to characteristics of the moving object.

3. The identification device according to claim 1 , wherein the control unit controls the scanning unit to illuminate the object while moving an irradiation position of the illumination light on a surface of the object.

4. The identification device according to claim 1 , wherein the control unit controls the scanning unit so that the illumination light does not remain at one point on the surface of the object.

5. 2. The identification device according to claim 1, wherein the scanning unit scans the illumination light in a moving direction of the object while scanning the illumination light in a direction perpendicular to the moving direction.

6. The identification device according to claim 1 , wherein the control unit controls the scanning unit to change a scanning condition of the illumination light based on information on a characteristic of the object.

7. The identification device according to claim 1 , wherein when a plurality of objects are present within a scannable range of the illumination light, the control unit determines the object to be identified based on information on characteristics of the objects.

8. 2. The apparatus of claim 1, wherein the information about the property of the object is the measured brightness of the object.

9. The identification device according to claim 1 , wherein the control unit changes a time for illuminating the object based on a brightness of the object.

10. 2. The identification device according to claim 1, wherein when a first object having a first brightness and a second object having a second brightness higher than the first brightness are illuminated while being scanned by the scanning unit, the control unit controls the scanning unit so that an illumination time for the first object is longer than an illumination time for the second object.

11. 2. The identification device according to claim 1, wherein the information on the characteristics of the object is information on at least one of a shape and a size of the object.

12. The identification device according to claim 1 , wherein the control unit controls the scanning unit based on the information and information related to a position of the object.

13. The identification device according to claim 2 , wherein the control unit controls the scanning unit based on the information and information relating to at least one of a conveying direction and a conveying speed of the moving object.

14. The identification device according to claim 1 , further comprising a recognition unit for acquiring information regarding characteristics of the object.

15. 2. The identification device according to claim 1, further comprising a processing unit that identifies the type of the object based on a result of light reception by the light receiving unit.

16. 16. The identification device according to claim 15, wherein the processing unit identifies the type of the object using data obtained by receiving, in advance, light from a sample illuminated with the illumination light by the light receiving unit.

17. 2. The identification device according to claim 1, further comprising a measurement unit for measuring a position of the object.

18. 2. The identification device according to claim 1, further comprising a measurement unit that measures at least one of a position and a speed of the moving object.

19. 2. The identification device according to claim 1, further comprising a spectroscopic unit that splits light from the object illuminated by the illumination light.

20. 2. The identification device according to claim 1, wherein the scanning unit is a galvanometer scanner.

21. the object is a resin; The identification device according to claim 15 , wherein the processing unit identifies a type of the resin.

22. 2. The identification device according to claim 1, further comprising a moving unit for moving the object.

23. 2. The identification device according to claim 1, wherein the light receiving section receives reflected light from the object illuminated by the illumination light.

24. 2. The identification device according to claim 1, wherein the light receiving section receives Raman scattered light from the object illuminated by the illumination light.

25. 2. The identification device according to claim 1, wherein the light receiving section receives scattered light from the object illuminated by the illumination light.

26. An identification device according to any one of claims 1 to 25; A sorting device comprising: a sorting unit that sorts objects based on the results of identification by the identification device.

27. 1. A method for identifying a type of object, comprising: a scanning step of scanning an illumination light that illuminates the object; a light receiving step of receiving light from the object illuminated by the illumination light, The identification method, wherein the scanning step scans the illumination light so as to illuminate the object based on information regarding a characteristic of the object.

28. an identification step of identifying the object using the identification method according to claim 27; and a sorting step of sorting the object based on a result of the identification step.

29. 27. A method for manufacturing an article, comprising: a sorting step of sorting objects using the sorting device according to claim 26; and a processing step of manufacturing an article by processing the objects sorted by the sorting step.

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