Resin type discrimination device, resin type discrimination method, and color determination method

Abstract

To provide a resin type discrimination device capable of discriminating a type of a resin with high accuracy corresponding to resins of respective colors such as white and black with a relatively small and inexpensive device constitution.SOLUTION: A resin type discrimination device includes: first measurement means that measures an absorption spectrum of infrared light of a resin; second measurement means that measures an absorption spectrum of infrared light of a resin in a sensitivity different from that of the first measurement means; color determination means that determines at least one of a color and a transmittance of the resin based on characteristic information of the resin measured by the first measurement means; switching means that switches between the first measurement means and the second measurement means; and type determination means that determines a type of the resin. The switching means performs measurement by switching between the first measurement means and the second measurement means based on a determination result of the color determination means. The type determination means determines the type of the resin based on data measured by at least the first measurement means among the first measurement means and the second measurement means.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to the configuration of a resin type discrimination device for discriminating resin / plastic types and its discrimination method, and particularly relates to a technique effective for resin type discrimination using infrared light.

Background Art

[0002] In plastic products or container-packaged plastics, plastics of various materials such as polyethylene, polystyrene, and polypropylene are used. In the recycling of waste plastics, the process of separating these plastic material types is essential.

[0003] A method of discriminating plastic types by infrared spectroscopy is known by utilizing the fact that the light absorption spectra differ for each plastic material type.

[0004] As the background art in this technical field, for example, there is a technique such as Patent Document 1. Patent Document 1 discloses a technique of acquiring a spectroscopic spectrum in the infrared region by a hyperspectral camera and performing resin identification.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the discrimination of resin types by infrared spectroscopy, when additives such as colorants are contained in the resin, in addition to the infrared absorption spectrum due to the resin type, the infrared absorbance spectrum of the additive is simultaneously observed, so accurate measurement may not be possible in some cases. In this case, particularly for dark-colored resins such as black, the infrared absorption spectrum may not be measurable, or an error may occur in the determination result of the resin type.

[0007] By improving the measurement sensitivity, it may be possible to measure the infrared absorbance spectrum by increasing the intensity of light absorption or scattering even for black resins. However, in the same high-sensitivity measurement, there is a concern that the signal intensity for white resins is too high and may saturate.

[0008] Therefore, a configuration in which the color of the resin is detected by another sensor that observes visible light such as a camera and the sensitivity is changed is conceivable, but there are problems leading to an increase in the cost and size of the apparatus.

[0009] In Patent Document 1 described above, the influence of the color of the resin on the measurement sensitivity as described above is not sufficiently considered, and there is room for improvement.

[0010] Therefore, an object of the present invention is to provide a resin type discrimination apparatus capable of highly accurate discrimination of resin types corresponding to resins of various colors such as white and black with a relatively small and inexpensive apparatus configuration, a resin type discrimination method using the same, and a color determination method.

Means for Solving the Problems

[0011] In order to solve the above problems, the present invention includes: a first measurement means for measuring the absorption spectrum of infrared light of a resin; a second measurement means for measuring the absorption spectrum of infrared light of the resin with a sensitivity different from that of the first measurement means; color determination means for determining at least one of the color and transmittance of the resin based on the characteristic information of the resin measured by the first measurement means; switching means for switching between the first measurement means and the second measurement means; and type determination means for determining the type of the resin. The switching means performs measurement by switching between the first measurement means and the second measurement means based on the determination result of the color determination means, and the type determination means determines the type of the resin based on at least the data measured by the first measurement means among the first measurement means and the second measurement means.

[0012] Further, the present invention provides a resin type discrimination method including: (a) irradiating infrared light onto a resin by first measurement means to measure characteristics of the resin; (b) receiving the resin characteristic information from the first measurement means, and determining at least one of the color and transmittance of the resin by color determination means; (c) determining whether to switch the measurement means by switching means based on the determination result in step (b); and (d) determining the type of the resin based on the resin characteristic information measured by the first measurement means.

[0013] Further, the present invention provides a color determination method including: (a) irradiating infrared light onto a resin by first measurement means to measure characteristics of the resin; (b) receiving the resin characteristic information from the first measurement means, and determining at least one of the color and transmittance of the resin by color determination means; (c) determining whether to switch the measurement means by switching means based on the determination result in step (b); and (d) determining the type of the resin based on the resin characteristic information measured by the first measurement means.

Advantages of the Invention

[0014] According to the present invention, it is possible to realize a resin type discrimination device capable of highly accurately discriminating the type of resin corresponding to various colors of resin such as white and black with a relatively small and inexpensive device configuration, a resin type discrimination method using the same, and a color determination method.

[0015] Thereby, regardless of the color of the resin, it is possible to discriminate the type thereof.

[0016] Problems, configurations, and effects other than those described above will be clarified by the description of the following embodiments.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4

Figure 5A

Figure 5B

Figure 6A

Figure 6B

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12A

Figure 12B

Mode for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing, the same components are denoted by the same reference numerals, and detailed descriptions of overlapping parts are omitted.

Examples

[0019] With reference to FIGS. 1 to 8, FIGS. 12A and 12B, a resin type discrimination apparatus according to Example 1 of the present invention, a resin type discrimination method using the same, and a color determination method will be described.

[0020] <<Outline of Example 1>> FIG. 1 is a diagram showing a schematic configuration of the resin type discrimination apparatus 10 of the present embodiment.

[0021] As shown in FIG. 1, the resin type discrimination apparatus 10 of the present embodiment includes a measurement unit 11 that measures the characteristics of the resin 20 with respect to the target resin 20, and a control unit 12 that controls the entire discrimination apparatus and determines the type of the resin 20 from the measured characteristics.

[0022] The measurement unit 11 irradiates the resin 20 with infrared light to determine the resin type, receives the light scattered and reflected from the resin 20, and acquires its characteristics. From the acquired characteristic measurement results, the control unit 12 determines the color information of the target resin 20. The color information to be determined is information such as whether the color is a dark color such as black that has low reflectance even in infrared light, or whether the color is a color such as white in which scattering and reflection are easily observed.

[0023] Based on the determination result of this color information, it is determined whether the resin type can be determined from the characteristic measurement results. If it is possible, the resin type is determined. On the other hand, when the color is such that it is difficult to determine the resin type, the measurement method of the measurement unit 11 is switched, the characteristics of the resin 20 are acquired again, and the resin type is determined using the re-acquired characteristic information.

[0024] <<Overall Configuration>> Using FIG. 1, the configuration of the resin type discrimination apparatus 10 of the present embodiment will be described in detail.

[0025] The resin type discrimination apparatus 10 includes a measurement unit 11, a control unit 12, a storage unit 13, and a display unit 14, and discriminates the material type of the resin 20.

[0026] The measurement unit 11 is configured to include a first measurement means 101 and a second measurement means 102. The measurement unit 11 has a function of measuring the characteristics of the resin 20. The measurement unit 11 and the control unit 12 are arranged in the same device and are connected by electrical wiring so that information can be exchanged. The control unit 12 receives the information on the characteristics of the resin 20 measured by the measurement unit 11. The control unit 12 is configured to include a color determination means 103, a switching means 104, and a type determination means 105.

[0027] The storage unit 13 is configured to include storage devices such as a ROM (Read Only Memory), a RAM (Random Access Memory), and an SSD (Solid State Drive). Programs and data for the operation of the control unit 12 are recorded in the storage unit 13.

[0028] The display unit 14 is composed of a display, an LED, etc. It is used to display the operation result of the resin type discrimination device 10.

[0029] ≪Overall operation≫ FIG. 2 is a flowchart showing the operation of the resin type discrimination device 10 of FIG. 1.

[0030] The resin type discrimination method of this embodiment will be described with reference to FIG. 2.

[0031] First, the process starts from step S201. At the time of step S201, it is assumed that the resin 20 is held at a predetermined position of the resin type discrimination device 10.

[0032] Step S202 is the first measurement step. Infrared light is irradiated onto the resin 20 by the first measurement means 101 in the measurement unit 11, and the characteristics of the resin 20 are measured.

[0033] Step S203 is the color determination step. The color determination means 103 in the control unit 12 receives the characteristic information of the resin 20 from the first measurement means 101 and determines the color of the resin 20.

[0034] Step S204 is a switching determination step. Based on the result of the color determination by the color determination means 103, the switching means 104 determines whether it is necessary to switch the measurement unit 11.

[0035] If switching is not required (F), the process proceeds to step S205. If switching is necessary (T), the process proceeds to step S206.

[0036] Step S205 is a first type determination step. The type determination means 105 determines the type of the resin 20 using the characteristic information of the resin 20 obtained by the first measurement means 101.

[0037] Step S206 is a measurement means switching step. Based on the result of the color determination by the color determination means 103, it is determined that switching of the measurement unit 11 is necessary (T), and the measurement means of the measurement unit 11 is switched from the first measurement means 101 to the second measurement means 102 by the control unit 12.

[0038] Step S207 is a second measurement step. The second measurement means 102 measures the characteristics of the resin 20.

[0039] Step S208 is a second type determination step. The type determination means 105 determines the type of the resin 20 based on the characteristic information measured by the second measurement means 102.

[0040] Finally, the process ends in step S209.

[0041] In this embodiment, the resin type discrimination device 10 will be described below as a device that the user uses while manually replacing the resin 20. Therefore, the resin 20 is removable from the resin type discrimination device 10, and during operation, the resin 20 is held at a predetermined position with respect to the resin type discrimination device 10. The determination result by the type determination means 105 is displayed on the display unit 14.

[0042] The details of each step will be described below.

[0043] <<First Measurement Step>> The first measurement step of step S202 will be described.

[0044] In the first measurement step (step S202), the characteristics of the resin 20 are measured by the first measurement means 101 shown in FIG. 1.

[0045] <<Configuration of the First Measurement Means 101>> FIG. 3A is a configuration diagram of the first measurement means 101. The first measurement means 101 includes a control unit 301a, a light source control unit 302a, a light source unit 303a, a spectroscopic measurement unit 304a, a signal amplification unit 305a, a spectroscopic control unit 306a, and a storage unit 307a.

[0046] The control unit 301a is a computer or a microcomputer that controls the light source unit 303a and acquires data, etc. The control unit 301a may be configured with the same hardware as the control unit 12 in FIG. 1.

[0047] The light source control unit 302a controls the light emission of the light source unit 303a according to the control of the control unit 301a. The light source control unit 302a is a general-purpose input / output (GPIO), a digital-to-analog converter, a current supply circuit, or a driver, etc.

[0048] The light source unit 303a is a light source that generates light in the infrared region. It is composed of one or more lamps or LEDs. In this embodiment, it is assumed to be composed of a plurality of LEDs with different wavelengths in the near-infrared region.

[0049] The spectroscopic measurement unit 304a is composed of a spectroscopic element that decomposes the reflected or scattered light from the resin 20 into wavelength components and a light receiver that converts light into an electrical signal. In this embodiment, it is a small spectroscopic element incorporating a wavelength filter using a Fabry-Perot interferometer and a photodiode. The wavelength of the infrared light received by the photodiode can be selected by the wavelength filter of the Fabry-Perot interferometer.

[0050] The spectroscopic measurement unit 304a may be a spectroscopic measuring instrument based on a principle other than using a Fabry - Perot interferometer. It may also be configured by an optical element that spatially separates light into wavelength components, such as a prism or a diffraction grating, and a spectroscopic measuring instrument in which a plurality of light - receiving surfaces are arranged in a line.

[0051] The signal amplification unit 305a is a circuit that amplifies the electrical signal generated by the spectroscopic measurement unit 304a according to the amount of received light. It is composed of an amplifier circuit, an analog - to - digital converter, etc.

[0052] The spectroscopic control unit 306a is a means for controlling the spectroscopic measurement unit 304a. It controls the wavelength selection of the Fabry - Perot interferometer built in the spectroscopic measurement unit 304a. It is composed of a digital - to - analog converter and an analog amplifier, etc.

[0053] The storage unit 307a is composed of storage devices such as a ROM (Read Only Memory), a RAM (Random Access Memory), and an SSD (Solid State Drive). In the storage unit 307a, the data of the wavelength selected by the spectroscopic control unit 306a and the data of the amount of received light acquired by the spectroscopic measurement unit 304a obtained via the signal amplification unit 305a are stored in association with each other. Also, a control program operating on the control unit 301a may be stored in the storage unit 307a. The storage unit 307a may be configured as the same hardware as the storage unit 13 in FIG. 1.

[0054] Regarding the arrangement of the light source unit 303a and the spectroscopic measurement unit 304a, in relation to the position where the resin 20 is arranged in the resin type discrimination device 10, they are arranged in a positional relationship such that the light emitted by the light source unit 303a is reflected or scattered by the resin 20 and can be received by the spectroscopic measurement unit 304a.

[0055] ≪Operation flow of the first measurement means 101≫ FIG. 4 is a flowchart showing the operation of the first measurement means 101.

[0056] First, the process starts from step S401.

[0057] Step S402 is a light source lighting step. The control unit 301a lights the light source unit 303a via the light source control unit 302a.

[0058] Step S403 is a wavelength setting step. The control unit 301a sets the minimum value of the measurement range in the wavelength filter of the spectroscopic measurement unit 304a via the spectroscopic control unit 306a.

[0059] Step S404 is a light reception amount measurement step. The control unit 301a acquires the light reception amount data of the spectroscopic measurement unit 304a via the signal amplification unit 305a.

[0060] Step S405 is a data recording step. The control unit 301a records the wavelength set in Step S403 and the light reception amount acquired in Step S404 in the storage unit 307a.

[0061] In Step S406, the measurement wavelength range is checked. If all the data in the predetermined wavelength range has not been acquired yet, the process returns to Step S403, and the setting of the wavelength filter of the spectroscopic measurement unit 304a is set to a wavelength that is one step higher in measurement resolution, and measurement is performed again. The processes of Steps S403, S404, and S405 are repeated. When it is confirmed in Step S406 that all the measurements in the measurement wavelength range have been completed, the process proceeds to Step S407.

[0062] Finally, the measurement process ends in Step S407.

[0063] In this embodiment, the first measurement means 101 is configured to change the wavelength in ascending order from the lower wavelength side for measurement, but it may also be configured to measure in descending order from the higher wavelength side.

[0064] ≪Measurement data of the first measurement means 101≫ FIGS. 5A and 5B show the measurement data acquired by the first measurement means 101. FIG. 5A shows an example of a light reception amount spectrum, and FIG. 5B shows an example of an infrared absorbance spectrum.

[0065] As shown in FIG. 5A, the data becomes a two-dimensional light reception amount spectrum having the value of the wavelength set in the wavelength filter of the spectroscopic measurement unit 304a on the horizontal axis and the value of the light reception amount data acquired from the signal amplification unit 305a on the vertical axis.

[0066] Calculations are performed for the measurement results in FIG. 5A in consideration of the electrical offset of the circuit unit of the first measurement means 101, the light source spectrum of the light source unit 303a, etc., to obtain an absorbance spectrum as shown in FIG. 5B. This absorbance spectrum shows the infrared light absorption characteristics of the target resin 20. For example, in FIG. 5A, a peak in absorbance is seen near a wavelength of 1680 nm. Since this characteristic varies depending on the type of resin such as polyethylene, polystyrene, polypropylene, etc., the resin type can be estimated from the light reception amount spectrum and absorbance spectrum as shown in FIGS. 5A and 5B.

[0067] ≪Color determination step≫ Returning to FIG. 2, the color determination step in step S203 will be described.

[0068] In the color determination step (step S203), the color of the resin 20 is determined by the color determination means 103 shown in FIG. 1.

[0069] ≪Explanation of color determination means 103≫ The color determination means 103 determines whether the color of the resin 20 is a color for which measurement of the infrared absorption spectrum is difficult.

[0070] Examples of the target data are shown in FIGS. 6A and 6B. FIG. 6A is an absorbance spectrum obtained by the first measurement means 101 similar to FIG. 5B. In this absorbance spectrum, near a wavelength of 1600 nm to 1800 nm, characteristics of absorption peaks due to the infrared absorption characteristics of the resin material can be seen. Near 1500 nm to 1580 nm shown by the broken line in FIG. 6A, no characteristics of infrared light absorption by the resin 20 are seen, and the data is flat.

[0071] Figure 6B shows the absorbance spectrum of a black resin made of the same resin material as in Figure 6A. The infrared absorption peak due to the resin in the vicinity of 1600 nm to 1800 nm is low, making measurement difficult. In the vicinity of 1500 nm to 1580 nm indicated by the broken line in Figure 6B, the average value of the absorbance is high, and the absorbance increases toward the shorter-wavelength visible region side.

[0072] The color determination means 103 determines whether the resin is a difficult-to-measure black resin using the average level and slope of the absorbance spectrum in a wavelength band where the infrared absorption peak due to the resin 20 is not observed.

[0073] In the black resin 20, the reason why the absorbance spectrum in the near-infrared region has such characteristics is due to the characteristics of the absorbance spectrum of the graphite added for coloring. Therefore, it can be measured regardless of the type of the resin 20, and a determination that is less affected by measurement errors due to the thickness of the material and other contaminants can be made.

[0074] Also, the black resin can be determined without the need for the absorbance spectrum in the visible region or other sensors such as a camera.

[0075] ≪Processing Flow of Color Determination Means 103≫ Figure 7 is a flowchart showing the operation of the color determination means 103. Using Figure 7, the operation of the color determination means 103 will be described.

[0076] First, the process starts from step S701.

[0077] Step S702 is a measurement result acquisition step. In the measurement result acquisition step, the measurement data measured by the first measurement means 101 is acquired.

[0078] Step S703 is a data separation step. In the data separation step, the data used for color determination is separated from the measurement data. For example, in the data separation step, the data in the vicinity of 1500 nm to 1580 nm is extracted from the measurement data.

[0079] Step S704 is an average level determination step. Calculate the average level of the data in the vicinity of 1500 nm to 1580 nm separated in step S703. If it is equal to or higher than a predetermined threshold value (T), proceed to step S705. If it is lower than the predetermined threshold value (F), proceed to step S706.

[0080] Step S705 is a slope determination step. Calculate the slope of the data in the vicinity of 1500 nm to 1580 nm separated in step S703. If the slope is a negative slope that decreases with respect to the wavelength and is equal to or lower than a predetermined threshold value (T), proceed to step S707. If the conditions are not met (F), proceed to step S706.

[0081] Step S706 is a normal color determination step. In this step, it is determined that the resin 20 to be measured is a resin of a normal color other than black.

[0082] Step S707 is a black color determination step. In this step, it is determined that the resin 20 to be measured is a black resin for which measurement is difficult.

[0083] Finally, the process ends in step S708.

[0084] Note that steps S704 and S705 may be interchanged in order.

[0085] ≪Switching determination step≫ Return to FIG. 2 and explain the switching determination step of step S204.

[0086] In the switching determination step (step S204), if it is determined in the previous color determination step (step S203) that the resin is a resin of a normal color other than black (F), it is determined that switching of the measuring means is unnecessary, and the process proceeds to step S205. On the other hand, if it is determined that the resin is a black resin (T), it is determined that switching of the measuring means is necessary, and the process proceeds to step S206.

[0087] ≪First type determination step≫ The first type determination step in step S205 will be described. In the first type determination step, the type of the resin 20 is determined using the infrared absorbance spectrum measured in the first measurement step S202. This process is performed by the type determination means 105 in FIG. 1.

[0088] ≪Operation of the type determination means 105≫ The operation of the type determination means 105 in FIG. 1 will be described. In the first type determination step S205 shown in FIG. 2, the type determination means 105 acquires the absorbance spectrum data measured by the first measurement means 101. For example, assuming that data as shown in FIG. 6A is acquired, the following description will be given.

[0089] The type determination means 105 determines the type of the resin 20 by comparing the characteristics of the absorbance spectrum of the resin 20 to be measured that it has acquired with the data of the clear samples of the resin material types stored in the storage unit 13 in advance.

[0090] The sample data stored in the storage unit 13 is, for example, data as shown in FIG. 8. In the graph of FIG. 8, the broken line indicates the absorbance spectrum data of polyethylene, the solid line indicates the absorbance spectrum data of polystyrene, and the dotted line indicates the absorbance spectrum data of polypropylene.

[0091] The type determination means 105 searches for the wavelength of the peak of the absorbance spectrum in FIG. 6A, which is the measurement data of the resin 20. In this embodiment, it is 1680 nm. Similarly, the wavelength of the peak is searched for in the sample data of FIG. 8 respectively. For polyethylene, it is 1735 nm, for polystyrene, it is 1680 nm, and for polypropylene, it is 1723 nm. By comparing these, since the peak wavelength of the absorbance spectrum of the resin 20 is closest to the absorbance of polystyrene in the sample data, the resin 20 is determined to be polystyrene.

[0092] The types of sample data are not limited to the above three types, and the number of data may increase. Also, since the absorbance spectrum of the sample data in this embodiment has a peak serving as a characteristic point in the vicinity of 1600 nm to 1800 nm, the wavelength band used by the aforementioned color determination means 103 is set as data in the vicinity of 1600 nm to 1800 nm. When changing the type of sample data and including a material having a characteristic point between 1500 nm and 1580 nm, the wavelength band used by the color determination means 103 is changed.

[0093] Also, when performing type determination based on the absorbance peak value, the data stored in the storage unit 13 may be only the numerical information of characteristic quantities such as the wavelength of the absorbance peak of the sample data instead of the absorbance spectrum. Thereby, since the data volume decreases, there is an advantage that the storage capacity required for the storage unit 13 is reduced.

[0094] The type determination process in the type determination means 105 may use a comparison method other than the comparison of the absorbance peak values described above. For example, a determination model such as an analyzer or machine learning is created from sample data of a known resin measured in advance and stored in the storage unit 13, and the measurement data of the resin 20 is subjected to type determination using these determination models.

[0095] <<Measurement means switching step>> Returning to FIG. 2, the measurement means switching step in step S206 will be described.

[0096] In the measurement means switching step (step S206), the measurement means used in the measurement unit 11 of FIG. 1 is switched, and the second measurement means 102 is operated.

[0097] <<Second measurement step>> Returning to FIG. 2, the second measurement step in step S207 will be described.

[0098] In the second measurement step (step S207), the characteristic data of the resin 20 is acquired by the second measurement means 102 of FIG. 1.

[0099] <<Configuration of the Second Measuring Means 102>> The second measuring means 102 will be described. FIG. 3B is a configuration diagram of the second measuring means 102. The second measuring means 102 includes a control unit 301b, a light source control unit 302b, a light source unit 303b, a spectroscopic measurement unit 304b, a signal amplification unit 305b, a spectroscopic control unit 306b, and a storage unit 307b.

[0100] The control unit 301b is a computer, a microcomputer, or the like that controls the light source unit 303b and acquires data. The control unit 301b may be configured with the same hardware as the control unit 12 in FIG. 1.

[0101] The configuration of the second measuring means 102 is similar to that of the first measuring means 101 shown in FIG. 3A, but the contents of the light source control unit 302b, the light source unit 303b, the spectroscopic measurement unit 304b, and the signal amplification unit 305b are different.

[0102] The light source control unit 302b and the light source unit 303b in the second measuring means 102 are installed so that the emission intensity is higher than that of the light source control unit 302a and the light source unit 303a in the first measuring means 101. That is, the total current supplied by the light source control unit 302b to the light source unit 303b increases. Alternatively, the number of lamps or LEDs arranged in the light source unit 303b increases.

[0103] In addition, the spectroscopic measurement unit 304b and the signal amplification unit 305b in the second measuring means 102 are installed so that the reception sensitivity is higher than that of the spectroscopic measurement unit 304a and the signal amplification unit 305a in the first measuring means 101. That is, the amplification factor of the analog amplifier in the signal amplification unit 305b increases. Alternatively, the sensitivity of the light receiver in the spectroscopic measurement unit 304b is set to be higher. To increase the sensitivity of the light receiver, the light receiving element is changed to one with a large light receiving area, or the photodetector using the photoelectric effect is changed to an avalanche photodiode with higher sensitivity.

[0104] Note that the second measurement means 102 may be configured by changing one or more of the components of the light source control unit 302a, the light source unit 303a, the spectroscopic measurement unit 304a, and the signal amplification unit 305a of the first measurement means 101 to the light source control unit 302b, the light source unit 303b, the spectroscopic measurement unit 304b, and the signal amplification unit 305b described above, and can perform measurement with higher sensitivity than the first measurement means 101. Therefore, measurement can be effectively performed on a black resin with less reflection and scattering.

[0105] Also, the second measurement means 102 may share some components with the first measurement means 101.

[0106] ≪Second type determination step≫ Returning to FIG. 2, the second type determination step in step S208 will be described.

[0107] In the second type determination step (step S208), the type of the resin 20 is determined using the infrared absorbance spectrum measured in the second measurement step S207. The content of this process is the same as that of the first type determination step (step S205) described above.

[0108] ≪Correction of infrared absorbance spectrum of black resin≫ The correction of the infrared absorbance spectrum of the black resin will be described with reference to FIGS. 12A and 12B. FIGS. 12A and 12B are diagrams showing examples of correction of measurement data.

[0109] In FIG. 2, before determining the type of the resin 20 in step S205, the infrared absorbance spectrum may be corrected. When the infrared absorbance spectrum shown by the solid line in FIG. 12A is measured, the subtraction data shown by the dotted line in FIG. 12A is subtracted. The subtraction data indicates the characteristics of the substance added for black dyeing.

[0110] The data in Fig. 12A uses the reference data pre-stored in the storage unit 13 of the resin type discrimination device 10. In the range of 1500 nm to 1580 nm enclosed by the dashed line in Fig. 12A, using the ratio of the value of the solid line measurement data to the value of the dotted line subtraction data as a coefficient, the reference data multiplied by the coefficient is used as the subtraction data. By this calculation, the influence of the absorption amount that changes due to the thickness of the material, the addition amount of the black additive, etc. is canceled out.

[0111] When the dotted line subtraction data in Fig. 12A is subtracted from the solid line measurement data in Fig. 12A, the correction data shown by the solid line in Fig. 12B can be obtained. The correction data in Fig. 12B has less influence of the infrared absorbance spectrum due to the black coloring additive, and in this example, a peak wavelength similar to the data of polystyrene shown by the solid line in Fig. 8 can be confirmed. Thereby, the accuracy of the determination result in the type determination step can be improved.

[0112] The dotted line subtraction data in Fig. 12A can also be obtained by calculating the envelope of the solid line measurement data in Fig. 12A.

[0113] ≪Measurement process completed≫ Returning to Fig. 2, step S209 is the measurement process completion step. By the previous first type determination step S205 or second type determination step S208, one type of the resin 20 has been determined. This determination result is displayed on the display unit 14 in Fig. 1 and transmitted to the device user.

[0114] ≪Modification example of the second measurement means 102≫ A modification example of the second measurement means 102 will be described.

[0115] The wavelengths of the light handled by the light source unit 303b and the spectroscopic measurement unit 304b, which are components of the second measurement means 102, are configured to handle light with a longer wavelength than the first measurement means 101. The first measurement means 101 measures the characteristics of the resin 20 based on the absorbance spectrum in the near-infrared region around a wavelength of 1500 nm to 1850 nm as shown in Figs. 5A and 5B.

[0116] In contrast, the second measurement means 102 uses a light source unit 303b and a spectroscopic measurement unit 304b having wavelengths in the mid-infrared wavelength region. For example, in the range of 3000 nm to 20000 nm, it is known that there are characteristic points of infrared light absorption of the resin 20 also in the mid-infrared wavelength band around 3500 nm. Since the absorbance spectrum of graphite added to the black resin tends to decrease in the absorption amount toward the long wavelength side, mid-infrared measurement is advantageous for the black resin.

[0117] In the case of this modification example, the storage unit 13 holds mid-infrared sample data in addition to the near-infrared sample data illustrated in FIG. 8. Mid-infrared sample data is used for the determination of the type of the resin 20 using the measurement data of the second measurement means 102.

[0118] In addition to this, discrimination may be performed using the principle of Raman scattering as the second measurement means 102. The second measurement means 102 when using the principle of Raman scattering uses a laser element as the light source unit 303b.

[0119] <<Modification Example of Color Determination Means 103>> The color determination means 103 may determine whether the color of the resin 20 is black or other dark colors using a visible-range camera (image sensor), a color sensor, or the like. In the case of this modification example, data sharing from the first measurement means 101 to the color determination means 103 is not performed. By using a visible-range sensor, color determination can be performed even when the resin colored with something other than graphite has low reflection and scattering in the near-infrared region.

[0120] <<Other Forms of Components>> The control unit 12 in the present embodiment is constituted by, for example, a CPU (Central Processing Unit) or the like. The processing performed by the control unit 12 is realized as software processing. These may exist as functional blocks in an integrated circuit such as an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit).

[0121] The function of the type determination means 105 may be configured to be included in the first measurement means 101 and the second measurement means 102.

[0122] The color determination means 103 may be configured to be included in the first measurement means 101.

Embodiment

[0123] With reference to FIGS. 9 to 11, a resin type discrimination apparatus according to Embodiment 2 of the present invention, a resin type discrimination method using the same, and a color determination method will be described.

[0124] ≪Configuration of the apparatus in the recycling plant≫ FIG. 9 shows another embodiment of the present invention. This embodiment is a configuration assuming a resin type discrimination apparatus in a recycling plant.

[0125] As shown in FIG. 9, the resin type discrimination apparatus 10 of this embodiment includes a measurement unit 11, a control unit 12, a storage unit 13, a display unit 14, a transport unit 906, and a sorting means 910, and discriminates the material type of the resin 20.

[0126] The measurement unit 11 includes a first measurement means 101, a second measurement means 102, and a position detection means 908. The measurement unit 11 has a function of measuring the characteristics of the resin 20.

[0127] The control unit 12 includes a color determination means 103, a switching means 104, a type determination means 105, and a transport control means 907.

[0128] The storage unit 13, the display unit 14, the first measurement means 101, the second measurement means 102, the color determination means 103, the switching means 104, and the type determination means 105 are the same components as those in Embodiment 1, and the description thereof will be omitted. The first measurement means 101 and the second measurement means 102 in this embodiment are installed at locations physically separated from the resin 20, and the resin 20 is moved to the measurement positions of the respective measurement means by the transport unit 906.

[0129] The measurement unit 11 and the control unit 12 operate as a series of systems, are connected by electrical wiring or wireless communication, and can exchange information. The control unit 12 receives information on the characteristics of the resin 20 measured by the measurement unit 11.

[0130] The conveying unit 906 is composed of a belt conveyor or the like. The resin 20 is conveyed by the conveying unit 906 to the vicinity of the resin type discrimination device 10.

[0131] The conveyance control means 907 controls the conveyance unit 906. When measurement by the second measurement means 102 becomes necessary by the switching means 104, the conveyance unit 906 conveys the resin 20 to a position suitable for measurement by the second measurement means 102.

[0132] The sorting means 910 sorts and displaces a plurality of resins 20 to two or more different positions by a robot, drive air, or the like. The sorting means 910 stores together the resins 20 determined to be of the same resin type based on the determination result of the type determination means 105.

[0133] The position detection means 908 detects the position of the resin 20 moving on the conveyance unit 906. The position detection means 908 is composed of a camera and identifies the position of the resin 20 by image recognition. The color determination means 103 may determine the color of the resin 20 from the video of the resin 20 taken by the position detection means 908.

[0134] ≪Overall operation≫ FIG. 10 is a flowchart showing the operation of the resin type discrimination device 10 of FIG. 9.

[0135] The resin type discrimination method of the present embodiment will be described with reference to FIG. 10.

[0136] First, the process starts from step S1001. At the time of step S1001, the resin 20 is mounted on the conveyance unit 906 of the resin type discrimination device 10.

[0137] Step S1002 is the first conveying step. The resin 20 is moved by the conveying unit 906 to a position where it can be measured by the first measuring means 101.

[0138] Step S1003 is the first measuring step, and the same processing as step S202 in FIG. 2 in Example 1 is performed to measure the properties of the resin 20.

[0139] Step S1004 is the color determination step, and the same processing as step S203 in FIG. 2 in Example 1 is performed to determine the color of the resin 20.

[0140] Step S1005 is the switching determination step, and the same processing as step S204 in FIG. 2 in Example 1 is performed to determine whether switching is necessary.

[0141] If switching is not required (F), the process proceeds to step S1006. If switching is required (T), the process proceeds to step S1008.

[0142] Step S1006 is the first type determination step, and the same processing as step S205 in FIG. 2 in Example 1 is performed to determine the type of the resin 20.

[0143] Step S1007 is the second conveying step. The resin 20 is moved by the conveying unit 906 to the position of the sorting means 910.

[0144] Step S1008 is the measuring means switching step, and the same processing as step S206 in FIG. 2 in Example 1 is performed to switch the measuring means.

[0145] Step S1009 is the third conveying step. The resin 20 is moved by the conveying unit 906 to a position where it can be measured by the second measuring means 102.

[0146] Step S1010 is the second measuring step, and the same processing as step S207 in FIG. 2 in Example 1 is performed, and the properties of the resin 20 are measured by the second measuring means 102.

[0147] Step S1011 is the second type determination step, which performs the same processing as step S208 in FIG. 2 in Embodiment 1 to determine the type of the resin 20.

[0148] Step S1012 is the fourth conveyance step. The conveyance unit 906 moves the resin 20 to the position of the sorting means 910.

[0149] Step S1013 is the sorting step. The sorting means 910 displaces the resin 20 to the position for each type based on the content of the resin type determination result.

[0150] Finally, the process ends at step S1014.

[0151] The result of the type determination means 105 is displayed on the display unit 14.

[0152] ≪Modification Examples of the First Measurement Means 101 and the Second Measurement Means 102≫ In this embodiment, the spectroscopic measurement units 304a and 304b of the first measurement means 101 and the second measurement means 102 may be configured by hyperspectral cameras.

[0153] FIG. 11 is a configuration example in which a hyperspectral camera is used for the first measurement means 101. The hyperspectral camera has a configuration in which a plurality of spectroscopic measurement elements are arranged in a straight line, and as shown in the measurement range 1101, spectroscopic measurement can be simultaneously performed on a plurality of measurement regions in a straight line.

[0154] The spectroscopic measurement unit 304 is arranged so that measurement can be performed when the conveyance unit 906 conveys the resin 20. The arrangement direction of the spectroscopic measurement regions of the spectroscopic measurement unit 304 is arranged in a direction substantially orthogonal to the conveyance direction of the conveyance unit 906.

[0155] The light source unit 303 is arranged at a position where light hits when the resin 20 enters the measurement range of the spectroscopic measurement unit 304.

[0156] While moving the resin 20 by the conveying unit 906, the spectroscopic measurement unit 304 intermittently performs measurement, so that measurement in a pseudo two-dimension can be performed.

[0157] In this embodiment, discrimination of types can be simultaneously performed for a plurality of resins 20. Thereby, there is an advantage that the processing time can be shortened for a large amount of resin 20.

[0158] In addition, in each of the above embodiments, an example of discrimination of resin types based on the infrared absorption spectrum has been shown, but it is also conceivable to perform discrimination of resin types based on other characteristic information such as the electrostatic characteristics and density of the resin.

[0159] Further, the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Also, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can also be added to the configuration of one embodiment. Also, for a part of the configuration of each embodiment, addition, deletion, and replacement with other configurations are possible.

Explanation of Reference Numerals

[0160] 10…Resin type discrimination device 11…Measurement unit 12…Control unit 13…Storage unit 14…Display unit 20…Resin 101…First measurement means 102…Second measurement means 103…Color determination means 104…Switching means 105…Type determination means 301a, 301b…Control unit 302a, 302b…Light source control unit 303, 303a, 303b…Light source unit 304, 304a, 304b…Spectroscopic measurement unit 305a, 305b…Signal amplification unit 306a, 306b... Spectral control unit 307a, 307b... Memory unit 906... Conveyor unit 907... Conveyor control means 908... Position detection means 910... Sorting means 1101... Measurement range.

Claims

1. a first measuring means for measuring the infrared light absorption spectrum of the resin; a second measuring means for measuring the infrared light absorption spectrum of the resin with a sensitivity different from that of the first measuring means; a color determination means for determining at least one of the color and transmittance of the resin based on the characteristic information of the resin measured by the first measuring means; a switching means for switching between the first measuring means and the second measuring means; a type determination means for determining the type of the resin, comprising: the switching means performs measurement by switching between the first measuring means and the second measuring means based on the determination result of the color determination means; the type determination means determines the type of the resin based on at least the data measured by the first measuring means among the first measuring means and the second measuring means. A resin type discrimination device characterized by this.

2. The resin type discrimination device according to claim 1, wherein the color determination means determines the color of the resin by using data in a predetermined wavelength range among the infrared light absorption spectra measured by the first measuring means. A resin type discrimination device characterized by this.

3. The resin type discrimination device according to claim 2, wherein the color determination means selects an infrared light absorption spectrum outside the wavelength region that is a characteristic point of the resin type to be discriminated and determines the color of the resin. A resin type discrimination device characterized by this.

4. The resin type discrimination device according to claim 1, wherein the color determination means determines whether the color of the resin is black based on the level and slope of the infrared light absorption spectrum. A resin type discrimination device characterized by this.

5. The resin type discrimination device according to claim 1, wherein the color determination means uses a wavelength including a wavelength range from 1500 nm to 1580 nm. A resin type discrimination device characterized by this.

6. The resin type discrimination device according to claim 1, wherein the second measuring means measures the infrared light absorption spectrum by measurement with higher sensitivity than the first measuring means. A resin type discrimination device characterized by this.

7. The resin type discrimination device according to claim 1, wherein the second measuring means shares some components with the first measuring means. A resin type discrimination device characterized by this.

8. The resin type discrimination device according to claim 1, wherein the second measuring means measures Raman scattered light. A resin type discrimination device characterized by this.

9. The resin type discrimination device according to claim 1, The resin type discrimination device is characterized in that the second measurement means measures an infrared light absorption spectrum using infrared light having a wavelength higher than that of the first measurement means.

10. The resin type discrimination device according to claim 1, wherein the color determination means is constituted by a camera or a color sensor having sensitivity in the visible light region.

11. The resin type discrimination device according to claim 1, wherein the type determination means corrects, with correction data indicating characteristics of a substance added for black dyeing, at least data measured by the first measurement means among the first measurement means and the second measurement means, and determines the type of the resin based on the corrected data.

12. A resin type discrimination method including the following steps: (a) irradiating the resin with infrared light by a first measurement means and measuring the characteristics of the resin; (b) receiving the characteristic information of the resin from the first measurement means and determining at least one of the color and the transmittance of the resin by a color determination means; (c) determining, based on the determination result in step (b), by a switching means whether it is necessary to switch the measurement means; (d) determining the type of the resin based on the characteristic information of the resin measured by the first measurement means.

13. The resin type discrimination method according to claim 12, wherein, in step (c), when it is determined that switching of the measurement means is not necessary, the type of the resin is determined based on the characteristic information of the resin measured by the first measurement means, and when it is determined that switching of the measurement means is necessary, the resin is irradiated with infrared light by a second measurement means having a sensitivity different from that of the first measurement means, the characteristics of the resin are measured, and the type of the resin is determined based on the characteristic information of the resin measured by the second measurement means.

14. A color determination method including the following steps: (a) irradiating the resin with infrared light by a first measurement means and measuring the characteristics of the resin; (b) receiving the characteristic information of the resin from the first measurement means and determining at least one of the color and the transmittance of the resin by a color determination means; (c) determining, based on the determination result in step (b), by a switching means whether it is necessary to switch the measurement means; Step of determining the type of the resin based on the characteristic information of the resin measured by the first measuring means.

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