Estimation device and estimation method

Abstract

An estimation device 1 estimates a material constituting solid waste 2. The estimation device 1 comprises: an incidence unit 11 that generates an electromagnetic wave having a frequency of 10 GHz to 10 THz and that makes the generated electromagnetic wave incident on solid waste in an incidence direction; a change unit 12 that changes the rotation angle of the incidence unit 11 rotating in the incidence direction with respect to the solid waste 2; a detection part 13 that detects an electromagnetic wave emitted from the solid waste 2 as a result of the electromagnetic wave being made incident on the solid waste 2 in each of a plurality of rotation angle states having different rotation angles; and an estimation unit 15 that estimates a material constituting the solid waste 2 on the basis of the intensity of the electromagnetic wave detected in each of the plurality of rotation angle states.

Description

Estimation device and estimation method

[0001] The present invention relates to an estimation device and an estimation method.

[0002] Solid waste (e.g., used acrylic sheets or discarded plastics) is sorted based on the materials that make up the solid waste, and each material is reused. Therefore, for example, when solid waste is reused by generating materials from the solid waste, if the solid waste is sorted with high precision, the purity of the generated materials can be increased.

[0003] For this reason, estimation devices that estimate the materials that make up solid waste are known. For example, the estimation device described in Patent Document 1 includes an incident unit that generates electromagnetic waves having a frequency of 10 GHz to 10 THz and directs the generated electromagnetic waves toward the solid waste in an incident direction. The estimation device further includes a detection unit that detects electromagnetic waves emitted from the solid waste when the electromagnetic waves are incident on the solid waste. In addition, the estimation device includes an estimation unit that estimates the materials that make up the solid waste based on the intensity of the detected electromagnetic waves.

[0004] Japanese Patent Application Laid-Open No. 2021-120625

[0005] After extensive research, the inventors of the present application discovered that the intensity of the detected electromagnetic waves can vary considerably depending on the rotation angle of the incident part around the incident direction relative to the solid waste. However, the estimation device described above cannot accurately reflect the change in the intensity of the electromagnetic waves that accompanies the change in the rotation angle in the estimation of the materials that make up the solid waste. As a result, the estimation device may provide excessively low accuracy in estimating the materials that make up the solid waste.

[0006] One of the objects of the present invention is to estimate with high accuracy the materials that make up solid waste.

[0007] In one aspect, an estimation device estimates materials constituting solid waste. The estimation device includes an incidence unit, a change unit, a detection unit, and an estimation unit. The incidence unit generates electromagnetic waves having a frequency of 10 GHz to 10 THz and directs the generated electromagnetic waves toward the solid waste in an incidence direction. The change unit changes the rotation angle of the incidence unit about the incidence direction relative to the solid waste. The detection unit detects electromagnetic waves emitted from the solid waste by directing the electromagnetic waves toward the solid waste at each of a plurality of rotation angle states having mutually different rotation angles. The estimation unit estimates the materials constituting the solid waste based on the intensities of the electromagnetic waves detected at each of the plurality of rotation angle states.

[0008] In another aspect, an estimation method estimates materials constituting solid waste, the estimation method including: an incidence step in which an incidence unit generates electromagnetic waves having a frequency of 10 GHz to 10 THz and causes the generated electromagnetic waves to be incident on the solid waste in an incidence direction; a detection step in which an incidence unit detects electromagnetic waves emitted from the solid waste as a result of the electromagnetic waves being incident on the solid waste; and a change step in which an incidence unit changes a rotation angle around the incidence direction with respect to the solid waste, thereby detecting electromagnetic waves emitted from the solid waste as a result of the electromagnetic waves being incident on the solid waste at each of a plurality of rotation angle states having mutually different rotation angles; and estimating the material based on the intensity of the electromagnetic waves detected at each of the plurality of rotation angle states.

[0009] The materials that make up solid waste can be estimated with high accuracy.

[0010] FIG. 1 is a block diagram conceptually showing the configuration of the estimation device of the first embodiment. FIG. 2 is a diagram showing the configuration of the incident unit, the modification unit, and the detection unit of the estimation device of the first embodiment. FIG. 3 is a diagram showing the solid waste, the placement table, and the second throttle unit of the estimation device of the first embodiment as viewed vertically from above. FIG. 4 is a diagram showing the configuration of the incident unit, the modification unit, and the detection unit of the estimation device of a modified example of the first embodiment. FIG. 5 is a graph showing the change in transmittance with respect to the rotation angle when the solid waste is an acrylic plate. FIG. 6 is a graph showing the average transmittance when the solid waste is various acrylic plates. FIG. 7 is a graph showing the change in transmittance with respect to the rotation angle when the solid waste is various plastic plates. FIG. 8 is a graph showing the average transmittance when the solid waste is various plastic plates.

[0011] Hereinafter, embodiments of an estimation device and an estimation method according to the present invention will be described with reference to FIGS.

[0012] First Embodiment (Overview) An estimation device according to a first embodiment estimates the materials constituting solid waste. The estimation device includes an incident unit that generates electromagnetic waves having a frequency of 10 GHz to 10 THz and directs the generated electromagnetic waves toward the solid waste in an incident direction, a change unit that changes the rotation angle of the incident unit about the incident direction relative to the solid waste, a detection unit that detects electromagnetic waves emitted from the solid waste as a result of the electromagnetic waves being incident on the solid waste at each of a plurality of rotation angle states having different rotation angles, and an estimation unit that estimates the materials based on the intensity of the electromagnetic waves detected at each of the plurality of rotation angle states.

[0013] According to this, the materials constituting the solid waste are estimated based on the intensity of the electromagnetic waves detected at each of a plurality of rotation angle states. As a result, even if the intensity of the detected electromagnetic waves varies relatively greatly depending on the rotation angle of the incident part about the incident direction relative to the solid waste, the change in the intensity of the electromagnetic waves accompanying the change in the rotation angle can be reflected with high accuracy in the estimation of the materials constituting the solid waste. As a result, the materials constituting the solid waste can be estimated with high accuracy. Next, the estimation device of the first embodiment will be described in more detail.

[0014] 1 and 2, the estimation device 1 includes an incident unit 11, a change unit 12, a detection unit 13, a storage unit 14, and an estimation unit 15. FIG. 1 is a block diagram conceptually illustrating the configuration of the estimation device 1. In FIG. 1, solid arrows and dotted arrows represent the propagation of electromagnetic waves and the transmission of information, respectively. FIG. 2 is a diagram illustrating the configuration of the incident unit 11, the change unit 12, and the detection unit 13. In FIG. 2, dashed lines and dashed-dotted lines represent the path along which the electromagnetic waves propagate (in other words, the optical path) and the optical axis, respectively.

[0015] The estimation device 1 estimates the materials that make up the solid waste 2. In this example, the solid waste 2 is waste made of materials whose main component is plastic. In this example, the solid waste 2 is a used acrylic plate. The acrylic plate is a plate made of acrylic resin. The acrylic resin is a polymer of acrylic ester or methacrylic ester.

[0016] The materials used to make acrylic sheets differ between those manufactured by the extrusion method and those manufactured by the casting method. The extrusion method involves extruding molten acrylic resin and casting it between rollers to form it into a sheet. The casting method involves casting molten acrylic resin between two glass sheets to form it into a sheet.

[0017] The solid waste 2 may be a container, bag, plastic wrap, film, home appliance parts, automobile parts, or wire coating made of a material primarily composed of plastic. For example, the container may be a bottle, tube, pack, cup, tray, or case. For example, the plastic may be ABS (Acrylonitrile Butadiene Styrene) resin, polycarbonate (PC), polyethylene terephthalate (PET), polyvinyl chloride (PVC), polypropylene (PP), or the like.

[0018] The solid waste 2 may also be a mass (i.e., a bale) of multiple compressed and packed containers. In this case, the containers may be made of a material containing polyethylene terephthalate as a main component (e.g., plastic bottles).

[0019] In this example, the estimation device 1 estimates whether the material constituting the solid waste 2 is a material constituting an acrylic plate manufactured by the extrusion method, or a material constituting an acrylic plate manufactured by the casting method.

[0020] The estimation device 1 may estimate whether the material constituting the solid waste 2 is made primarily of ABS resin, polycarbonate, polyethylene terephthalate, polyvinyl chloride, or polypropylene.

[0021] As shown in FIG. 2 , the incident unit 11 includes an electromagnetic wave generating unit 11a, a first aperture unit 11b, and a lens unit 11c. The electromagnetic wave generating unit 11a generates electromagnetic waves having a frequency of 10 GHz to 10 THz (in other words, sub-terahertz waves or terahertz waves). Note that, in this specification, sub-terahertz waves or terahertz waves may be referred to as light. In this example, the frequency of the electromagnetic waves generated by the electromagnetic wave generating unit 11a is 140 GHz. Note that the frequency of the electromagnetic waves generated by the electromagnetic wave generating unit 11a may be a frequency different from 140 GHz. For example, the frequency of the electromagnetic waves generated by the electromagnetic wave generating unit 11a is preferably 40 GHz to 400 GHz.

[0022] In this example, the electromagnetic wave generating unit 11a includes a GUNN diode, an IMPATT (Impact Avalanche and Transit Time) diode, or a resonant tunneling diode (RTD). Note that the electromagnetic wave generating unit 11a may also include an oscillator using a CMOS (Complementary Metal-Oxide-Semiconductor) and a frequency multiplier (for example, a phase-locked loop) that multiplies the frequency of the electromagnetic wave generated by the oscillator by n (n is a real number greater than 1).

[0023] In this example, the electromagnetic wave generating unit 11a generates a continuous wave. Alternatively, the electromagnetic wave generating unit 11a may generate a pulsed wave. For example, the diode included in the electromagnetic wave generating unit 11a may operate at high speed, for example, for a time period of several picoseconds to several hundred picoseconds.

[0024] The first throttle section 11b is located between the electromagnetic wave generator 11a and the lens section 11c and allows only a portion of the electromagnetic waves generated by the electromagnetic wave generator 11a to pass through. In this example, the first throttle section 11b has a hollow truncated conical shape with a central axis extending along a first straight line L1 connecting the solid waste 2 and the position where the electromagnetic waves are emitted from the electromagnetic wave generator 11a. The inner diameter of the first throttle section 11b increases from the electromagnetic wave generator 11a toward the lens section 11c.

[0025] In this example, the solid waste 2 has a flat plate shape extending along a plane perpendicular to the first line L1. In this example, the first line L1 extends in the z-axis direction. In this example, the first line L1 constitutes a line through which the optical axis of the lens portion 11c passes.

[0026] The lens unit 11c converts the electromagnetic waves generated by the electromagnetic wave generating unit 11a and passed through the first diaphragm unit 11b into parallel light parallel to the first straight line L1. In other words, the lens unit 11c has a position where the position at which the electromagnetic waves are emitted from the electromagnetic wave generating unit 11a coincides with the focal point of the lens unit 11c.

[0027] In this example, the lens portion 11c is a plano-convex lens made of polytetrafluoroethylene. Instead of a plano-convex lens, the lens portion 11c may be a biconvex lens or a concave lens. The lens portion 11c may also be made of high-resistivity silicon. For example, high-resistivity silicon is manufactured using a float zone method (in other words, a floating casting method).

[0028] In this way, the incident unit 11 converts the electromagnetic waves generated by the electromagnetic wave generating unit 11a into parallel light parallel to the first straight line L1 passing through the electromagnetic wave generating unit 11a and the solid waste 2 via the first diaphragm unit 11b and the lens unit 11c, and causes the converted parallel light to be incident on the solid waste 2. In this example, the direction along the first straight line L1 (in other words, the z-axis direction) corresponds to the incident direction.

[0029] The change unit 12 changes the rotation angle of the incident unit 11 about the incident direction relative to the solid waste 2. In this example, the change unit 12 changes the rotation angle of the incident unit 11 about the incident direction relative to the solid waste 2 by rotating the solid waste 2 about the first straight line L1 without rotating the incident unit 11. Note that the change unit 12 may also be configured to change the rotation angle of the incident unit 11 about the incident direction relative to the solid waste 2 by rotating the incident unit 11 about the first straight line L1 without rotating the solid waste 2.

[0030] 2, the changing unit 12 includes a mounting table 12a. The mounting table 12a has a hole 12a1 at its center, on which the solid waste 2 is placed and which penetrates in the incident direction. In this example, the mounting table 12a is hollow and cylindrical, with its central axis extending along a first straight line L1. The mounting table 12a is supported so as to be rotatable about the first straight line L1.

[0031] In this way, the change unit 12 changes the rotation angle of the incident unit 11 around the incident direction relative to the solid waste 2 by rotating the platform 12a on which the solid waste 2 is placed around the first straight line L1.

[0032] The detector 13 is located in a region vertically below the hole 12a1 of the mounting table 12a. Alternatively, the detector 13 may be located in the hole 12a1 of the mounting table 12a. In this example, as shown in FIG. 2, the detector 13 includes a second aperture section 13a and an electromagnetic wave detector 13b.

[0033] The second narrowing section 13a passes only a portion of the electromagnetic waves that have passed through the solid waste 2 between the solid waste 2 and the electromagnetic wave detection section 13b. In this example, the second narrowing section 13a is a hollow truncated cone-shaped cylinder whose central axis extends along the first straight line L1. The inner diameter of the second narrowing section 13a decreases from the solid waste 2 toward the electromagnetic wave detection section 13b.

[0034] As shown in Figure 3, which shows the solid waste 2, the loading platform 12a, and the second constriction section 13a viewed from vertically above, the inner diameter of the second constriction section 13a at the vertically upper end (in other words, the upper end) (in other words, the maximum inner diameter of the second constriction section 13a) is smaller than the inner diameter of the loading platform 12a (in other words, the diameter of the hole 12a1).

[0035] In this example, as shown in Fig. 2, the opening at the upper end of the second diaphragm portion 13a is narrower than the region through which the parallel light converted by the lens portion 11c passes (in other words, the parallel light passing region), and is included in the parallel light passing region. Note that, as shown in Fig. 4, the opening at the upper end of the second diaphragm portion 13a may substantially coincide with the parallel light passing region. Alternatively, the opening at the upper end of the second diaphragm portion 13a may be wider than the parallel light passing region so as to include the parallel light passing region.

[0036] The electromagnetic wave detection unit 13b detects electromagnetic waves that have passed through the solid waste 2 and the second restricting unit 13a. In this example, the electromagnetic wave detection unit 13b includes a Schottky barrier diode and detects the electromagnetic waves using the Schottky barrier diode. For example, the diode included in the electromagnetic wave detection unit 13b may operate at a high speed of several picoseconds to several hundred picoseconds.

[0037] In this example, the electromagnetic waves that are incident on the solid waste 2 by the incident unit 11 and that have passed through the solid waste 2 (in other words, transmitted waves) correspond to the electromagnetic waves that have been emitted from the solid waste 2. In other words, in this example, the detection unit 13 detects the intensity of the electromagnetic waves that have passed through the solid waste 2 and have been emitted from the solid waste 2.

[0038] The detection unit 13 detects electromagnetic waves that are incident on the solid waste 2 by the incident unit 11 and that have passed through the solid waste 2 (in other words, electromagnetic waves that are emitted from the solid waste 2 as a result of the electromagnetic waves being incident on the solid waste 2) in each of a plurality of rotation angle states in which the rotation angle of the incident unit 11 around the first straight line L1 relative to the solid waste 2 is different from one another.

[0039] In this example, the change unit 12 changes the rotation angle of the incident unit 11 about the first line L1 relative to the solid waste 2, thereby sequentially setting the state of the estimation device 1 to each of a plurality of rotation angle states. In this example, the change unit 12 rotates the mounting table 12a using electricity. Note that the change unit 12 may also be rotated manually by a user of the estimation device 1.

[0040] The storage unit 14 stores transmittance information. The transmittance information is information in which transmittance and material are associated with each other. The transmittance is the ratio of the intensity of the electromagnetic wave that passes through the solid waste 2 to the intensity of the electromagnetic wave that is incident on the solid waste 2.

[0041] The estimation unit 15 estimates the materials that make up the solid waste 2 based on the intensity of the electromagnetic waves detected by the detection unit 13 at each of the multiple rotation angle states and the transmittance information stored in the memory unit 14.

[0042] In this example, the plurality of rotation angle states are M states in which the rotation angle of the incident portion 11 around the first straight line L1 relative to the solid waste 2 differs by 360 / M degrees, where M is an integer equal to or greater than 2. In this example, M is 8.

[0043] In this example, the estimation unit 15 estimates the material that constitutes the solid waste 2 based on the average value of the intensity of the electromagnetic waves detected by the detection unit 13 for multiple rotation angle states and the transmittance information stored in the memory unit 14.

[0044] In this example, the estimation unit 15 calculates the average transmittance by dividing the average value of the intensity of the electromagnetic waves detected by the detection unit 13 for a plurality of rotation angle states by the intensity of the electromagnetic waves incident on the solid waste 2, and estimates the material that constitutes the solid waste 2 based on the calculated average transmittance and the transmittance information stored in the memory unit 14. The average transmittance is a value obtained by averaging the transmittance for a plurality of rotation angle states.

[0045] The estimation device 1 may use transmission intensity instead of transmittance. Transmission intensity is the intensity of electromagnetic waves that pass through the solid waste 2. The estimation device 1 may also use reflected waves instead of transmitted waves. Reflected waves are electromagnetic waves that are reflected by the solid waste 2 and are emitted from the solid waste 2. In this case, the detection unit 13 detects the intensity of the reflected waves.

[0046] (Operation) Next, the operation of the estimation device 1 will be described. First, the solid waste 2 is placed on the placement table 12a. Next, the incident step, the detection step, and the change step are sequentially repeated M times. Note that the Mth change step does not necessarily have to be performed.

[0047] In the incident step, the incident unit 11 generates electromagnetic waves having a frequency of 10 GHz to 10 THz and makes the generated electromagnetic waves incident on the solid waste 2 in an incident direction. In the detection step, the detection unit 13 detects electromagnetic waves emitted from the solid waste 2 when the electromagnetic waves are incident on the solid waste 2 by the incident unit 11. In the change step, the change unit 12 changes the rotation angle of the incident unit 11 about the first line L1 relative to the solid waste 2.

[0048] As a result, the detection unit 13 detects electromagnetic waves emitted from the solid waste 2 by the electromagnetic waves being incident on the solid waste 2 at each of M rotation angle states in which the rotation angle of the incident unit 11 around the first straight line L1 relative to the solid waste 2 is different from one another.

[0049] Then, the estimation unit 15 estimates the materials that make up the solid waste 2 based on the intensity of the electromagnetic waves detected by the detection unit 13 at each of the multiple rotation angle states and the transmittance information stored in the memory unit 14.

[0050] As described above, the estimation device 1 of the first embodiment estimates the materials that make up the solid waste 2. The estimation device 1 includes an incident unit 11, a change unit 12, a detection unit 13, and an estimation unit 15.

[0051] The incident unit 11 generates electromagnetic waves having a frequency of 10 GHz to 10 THz and directs the generated electromagnetic waves toward the solid waste 2 in an incident direction. The change unit 12 changes the rotation angle of the incident unit 11 about the incident direction relative to the solid waste 2 (in this example, the first straight line L1). The detection unit 13 detects electromagnetic waves emitted from the solid waste 2 by the electromagnetic waves being incident on the solid waste 2 at each of a plurality of rotation angle states with different rotation angles. The estimation unit 15 estimates the materials constituting the solid waste 2 based on the intensity of the electromagnetic waves detected at each of the plurality of rotation angle states.

[0052] According to this, the materials constituting the solid waste 2 are estimated based on the intensity of the electromagnetic waves detected at each of a plurality of rotation angle states. As a result, even if the intensity of the detected electromagnetic waves varies relatively greatly depending on the rotation angle of the incident part 11 around the incident direction relative to the solid waste 2, the change in the intensity of the electromagnetic waves accompanying the change in the rotation angle can be reflected with high accuracy in the estimation of the materials constituting the solid waste 2. As a result, the materials constituting the solid waste 2 can be estimated with high accuracy.

[0053] Furthermore, in the estimation device 1 of the first embodiment, the change unit 12 includes a mounting base 12a having a hole 12a1 at its center on which the solid waste 2 is placed and which penetrates in the incident direction, and which is supported so as to be rotatable around the incident direction. The detection unit 13 detects electromagnetic waves in the hole 12a1 or in a region vertically below the hole 12a1.

[0054] This allows the rotation angle of the incident portion 11 around the incident direction relative to the solid waste 2 to be easily changed by rotating the mounting base 12a without changing the area where the electromagnetic waves are incident on the solid waste 2. Furthermore, the intensity of the electromagnetic waves that pass through the solid waste 2 and the hole 12a1 in the center of the mounting base 12a is detected. Therefore, the influence of the mounting base 12a on the detected electromagnetic waves can be suppressed. As a result, the materials that make up the solid waste 2 can be estimated with high accuracy.

[0055] Furthermore, in the estimation device 1 of the first embodiment, the estimation unit 15 estimates the materials that make up the solid waste 2 based on the average value of the electromagnetic wave intensity for a plurality of rotation angle states.

[0056] Incidentally, after extensive research, the inventors of the present application have found that even when the strength of the detected electromagnetic waves fluctuates relatively greatly depending on the rotation angle of the incident portion 11 around the incident direction relative to the solid waste 2, there is a strong correlation between the average value of the electromagnetic wave strength over multiple rotation angle states and the materials that make up the solid waste 2. Therefore, the estimation device 1 can estimate the materials that make up the solid waste 2 with high accuracy.

[0057] 5 shows the change in transmittance with respect to the rotation angle of the incident portion 11 about the first line L1 relative to the solid waste 2 when the solid waste 2 is an acrylic plate. The solid waste 2 is a transparent flat plate with a thickness of 4 mm. In FIG. 5, the black squares represent acrylic plates manufactured by the casting method, and the black triangles represent acrylic plates manufactured by the extrusion method.

[0058] Incidentally, the larger the molecular weight of a material, the longer the molecular chain of that material tends to be, and therefore it is estimated that the intensity of the detected electromagnetic waves tends to fluctuate relatively greatly depending on the rotation angle of the incident part 11 about the first line L1 relative to the solid waste 2. In addition, the molecular weight of the material that makes up the acrylic plate manufactured by the extrusion method is significantly smaller than the molecular weight of the material that makes up the acrylic plate manufactured by the casting method.

[0059] Therefore, as shown in Figure 5, the transmittance of an acrylic plate manufactured by the casting method varies relatively more greatly depending on the rotation angle of the incident portion 11 around the first straight line L1 relative to the solid waste 2 than that of an acrylic plate manufactured by the extrusion method.

[0060] Fig. 6 shows the average transmittance when the solid waste 2 is various acrylic plates. The average transmittance is the transmittance averaged over M rotation angle states. From left to right, Fig. 6 shows the average transmittance for a white flat plate manufactured by extrusion and having a thickness of 5 mm, a white flat plate manufactured by casting and having a thickness of 5 mm, a black flat plate manufactured by extrusion and having a thickness of 5 mm, a black flat plate manufactured by casting and having a thickness of 5 mm, a transparent flat plate manufactured by extrusion and having a thickness of 4 mm, and a transparent flat plate manufactured by casting and having a thickness of 4 mm.

[0061] Thus, in this example, when the thickness and color of the acrylic plate match, it is possible to estimate with high accuracy, depending on the average transmittance, whether the material constituting the solid waste 2 is the material constituting the acrylic plate manufactured by the extrusion method or the material constituting the acrylic plate manufactured by the casting method.

[0062] For example, if the average transmittance is smaller than a predetermined threshold, the estimation unit 15 estimates that the material constituting the solid waste 2 is a material constituting an acrylic plate manufactured by an extrusion method, and if the average transmittance is greater than the threshold, the estimation unit 15 estimates that the material constituting the solid waste 2 is a material constituting an acrylic plate manufactured by a casting method. This makes it possible to estimate the material constituting the solid waste 2 with high accuracy. For example, the threshold may be set according to the thickness and color of the acrylic plate.

[0063] 7 shows the change in transmittance with respect to the rotation angle of the incident portion 11 about the first line L1 relative to the solid waste 2 when the solid waste 2 is various plastic plates. The solid waste 2 is a transparent flat plate with a thickness of 5 mm. In FIG. 7, the black squares represent plastic plates made of polypropylene (PP), the black diamonds represent plastic plates made of polyvinyl chloride (PVC), the black triangles represent plastic plates made of polyethylene terephthalate (PET), the black circles represent plastic plates made of polycarbonate (PC), and the open squares represent plastic plates made of ABS resin.

[0064] As shown in FIG. 7, the transmittance of a plastic plate made of PET or PC varies more significantly than that of other plastic plates depending on the rotation angle of the incident portion 11 relative to the solid waste 2 about the first straight line L1.

[0065] Figure 8 shows the average transmittance when the solid waste 2 is made of various plastic plates. The plastic plates in Figure 8 are the same as those in Figure 7. As can be seen, in this example, it is possible to estimate with high accuracy whether the material constituting the solid waste 2 is primarily made of ABS resin, polycarbonate, polyethylene terephthalate, polyvinyl chloride, or polypropylene, depending on the average transmittance.

[0066] For example, if the average transmittance is a value between an upper limit and a lower limit predetermined for each material, the estimation unit 15 estimates that the material making up the solid waste 2 is that material. This makes it possible to estimate with high accuracy the material making up the solid waste 2. For example, the upper limit and lower limit for each material may be set according to the thickness and color of the plastic plate.

[0067] Second Embodiment Next, an estimation device of a second embodiment will be described. The estimation device of the second embodiment differs from the estimation device of the first embodiment in that the estimation device estimates a material based on a dispersion parameter that indicates the degree to which the intensity of an electromagnetic wave is dispersed among a plurality of rotation angle states. The following description will focus on the differences. In the description of the second embodiment, components that are assigned the same reference numerals as those used in the first embodiment are the same or substantially similar.

[0068] The storage unit 14 of the second embodiment stores transmittance dispersion information. The transmittance dispersion information is information in which dispersion parameters, which indicate the degree to which transmittance varies with respect to a plurality of rotation angle states, are associated with materials. For example, the dispersion parameters may be standard deviation, variance, the magnitude of the difference between the maximum and minimum values, the interquartile range, or the interquartile deviation.

[0069] In this example, the dispersion parameter is a parameter that increases as the degree to which the intensity of the electromagnetic wave is dispersed among a plurality of rotation angle states increases. Alternatively, the dispersion parameter may be a parameter that decreases as the degree to which the intensity of the electromagnetic wave is dispersed among a plurality of rotation angle states increases.

[0070] The estimation unit 15 of the second embodiment estimates the materials constituting the solid waste 2 based on a dispersion parameter that represents the degree to which the intensity of the electromagnetic waves detected by the detection unit 13 is dispersed across multiple rotation angle states and transmittance dispersion information stored in the memory unit 14.

[0071] Incidentally, the larger the molecular weight of the material making up the solid waste 2, the longer the molecular chain of that material is likely to be, and therefore it is estimated that the intensity of the detected electromagnetic waves is likely to fluctuate relatively greatly depending on the rotation angle of the incident part 11 about the first straight line L1 relative to the solid waste 2. Furthermore, there is a strong correlation between the size of the molecular weight of the material making up the solid waste 2 and the material making up the solid waste 2. In other words, the dispersion parameter can reflect the material making up the solid waste 2 with high accuracy.

[0072] Therefore, the estimation device 1 of the second embodiment can estimate with high accuracy the materials that make up the solid waste 2. For example, as shown in Figures 5 and 7, the degree to which the transmittance varies with the rotation angle of the incident part 11 about the first line L1 relative to the solid waste 2 varies relatively greatly for each material that makes up the solid waste 2. Therefore, the materials that make up the solid waste 2 can be estimated with high accuracy.

[0073] Furthermore, in the estimation device 1 of the modified example of the second embodiment, if the dispersion parameter for the solid waste 2 is smaller than a predetermined threshold, the estimation unit 15 estimates that the material constituting the solid waste 2 is a material for material recycling that is to be processed for material recycling, and on the other hand, if the dispersion parameter for the solid waste 2 is larger than the threshold, the estimation unit 15 estimates that the material constituting the solid waste 2 is a material for chemical recycling that is to be processed for chemical recycling.

[0074] The materials used to make acrylic sheets differ between those manufactured by extrusion and those manufactured by casting. The molecular weight of the material used to make acrylic sheets manufactured by extrusion is significantly smaller than that of the material used to make acrylic sheets manufactured by casting.

[0075] Furthermore, the materials used to make acrylic sheets manufactured by the extrusion method are often materials for material recycling, while the materials used to make acrylic sheets manufactured by the casting method are often materials for chemical recycling. As such, the molecular weight of materials for material recycling is often smaller than that of materials for chemical recycling.

[0076] Therefore, according to the estimation device 1 of the modified example of the second embodiment, it is possible to estimate with high accuracy whether the material constituting the solid waste 2 is a material for material recycling or a material for chemical recycling.

[0077] The present invention is not limited to the above-described embodiment. For example, various modifications that can be understood by those skilled in the art may be made to the above-described embodiment without departing from the spirit of the present invention.

[0078] For example, the estimation device 1 may estimate the materials constituting the solid waste 2 based on both the average value of the intensity of the electromagnetic waves detected by the detection unit 13 over multiple rotation angle states and a dispersion parameter that represents the degree to which the intensity of the electromagnetic waves detected by the detection unit 13 disperses over multiple rotation angle states.

[0079] REFERENCE SIGNS LIST 1 Estimation device 11 Incident unit 11a Electromagnetic wave generation unit 11b First aperture unit 11c Lens unit 12 Change unit 12a Placement base 12a1 Hole 13 Detection unit 13a Second aperture unit 13b Electromagnetic wave detection unit 14 Memory unit 15 Estimation unit 2 Solid waste

Claims

1. An estimation device for estimating the materials that make up solid waste, comprising: an incident unit that generates electromagnetic waves having a frequency of 10 GHz to 10 THz and makes the generated electromagnetic waves incident on the solid waste in an incident direction; a change unit that changes the rotation angle of the incident unit around the incident direction with respect to the solid waste; a detection unit that detects electromagnetic waves emitted from the solid waste as the electromagnetic waves are incident on the solid waste at each of a plurality of rotation angle states where the rotation angle is different from each other; and an estimation unit that estimates the material based on the intensity of the electromagnetic waves detected at each of the plurality of rotation angle states.

2. An estimation device as described in claim 1, wherein the modification unit comprises a mounting base having a hole in the center on which the solid waste is placed and which passes through in the incident direction, and which is supported so as to be rotatable around the incident direction, and the detection unit detects the electromagnetic waves in the hole or in the area vertically below the hole.

3. An estimation device according to claim 1 or 2, wherein the estimation unit estimates the material based on an average value of the intensity of the electromagnetic wave for the plurality of rotation angle states.

4. An estimation device according to claim 1 or 2, wherein the estimation unit estimates the material based on a dispersion parameter that indicates the degree to which the intensity of the electromagnetic wave is dispersed for the plurality of rotation angle states.

5. An estimation device as described in claim 4, wherein the dispersion parameter increases as the degree to which the intensity of the electromagnetic wave is dispersed among the plurality of rotation angle states increases, and the estimation unit estimates that the material is a material for material recycling that is to be processed in material recycling when the dispersion parameter for the solid waste is smaller than a threshold value, and on the other hand, estimates that the material is a material for chemical recycling that is to be processed in chemical recycling when the dispersion parameter for the solid waste is larger than the threshold value.

6. A method for estimating the materials constituting solid waste, comprising: an incidence step in which an incidence unit generates electromagnetic waves having a frequency of 10 GHz to 10 THz and causes the generated electromagnetic waves to be incident on the solid waste in an incident direction; a detection step in which the electromagnetic waves are incident on the solid waste and the electromagnetic waves are detected as being emitted from the solid waste; and a change step in which the rotation angle of the incidence unit around the incident direction with respect to the solid waste is changed. By sequentially repeating these steps, the method detects the electromagnetic waves emitted from the solid waste as the electromagnetic waves are incident on the solid waste at each of a plurality of rotation angle states where the rotation angle is different from each other, and estimates the material based on the intensity of the electromagnetic waves detected at each of the plurality of rotation angle states.

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