JP2002267599A - Quality of material identification system for plastic and quality of material identification/assortment system for plastic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the quality of material identification system for plastic capable of identifying the quality of material of plastic even if mixed substances containing several kinds of plastic are carried without orientating the substances in a carrying means. SOLUTION: This identification system is equipped with a carrying means for carrying the mixed substances containing several kinds of plastic; an irradiation means for applying near infrared to the mixed substances carried with the carrying means; an imaging member having three or more kinds of band- path filters having different wavelengths in which reflected light from the mixed substances irradiated with the near infrared is incident; and an identification means for comparing the amounts of reflected light in the region of the imaging member based on the same kind of plastic of the regions of the imaging member in which the reflected light from each plastic within the near infrared irradiation region of the mixed substances is incident through three or more kinds of band- pas filters, and for identifying the quality of material of plastic in the mixed substances from the difference between the amounts of reflected light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a plastic material identification system and a plastic material identification / separation system.

[0002]

2. Description of the Related Art Conventionally, regarding the separation of waste plastics, it has been known to separate plastics by utilizing the difference in specific gravity of plastics using a hydrocyclone.

[0003] However, plastics having substantially the same specific gravity, for example, polyethylene (0.93) and polypropylene (0.90 to 0.91) cannot be separated. Further, in the prior art, it was difficult to separate plastic having no (small) difference in specific gravity.

[0004] For this reason, Japanese Patent Application Laid-Open No. 9-8976 discloses
No. 8 discloses a pretreatment sorting device for roughly separating plastics, a transport device for aligning and transporting pretreated plastics, a light source for irradiating near-infrared light to the plastics, and a light source for irradiating the plastics with light from the light source. A plastic material identification device comprising a light receiving element for detecting transmitted light or reflected light from a device, and an identification device for identifying a material based on absorbance of a specific wavelength by the plastic, and a classification device controlled by the identification device Is disclosed.

[0005]

However, the conventional plastic material identification device requires a device for aligning the plastic on a conveyor such as a conveyor, which not only increases the cost of the device but also increases the throughput of the plastic. There was a problem that was limited.

An object of the present invention is to provide a plastic material identification system capable of identifying a plastic material even if a mixed material containing a plurality of types of plastics is transported without being arranged on a transporting means. is there.

[0007] The present invention provides a plastic which can identify the material of the plastic and automatically sort the specific plastic even if the mixed material containing a plurality of kinds of plastics is transported without being arranged on the transporting means. And a material identification and classification system.

[0008]

According to the present invention, there is provided a plastic material identification system, comprising: conveying means for conveying a mixture containing a plurality of types of plastics; and near-infrared light to the mixture conveyed by the conveyance means. Irradiating means for irradiating, an imaging member comprising a CCD camera or an imaging tube each having three or more types of bandpass filters having different wavelengths at which reflected light from the mixture irradiated with near infrared rays is incident, and The CCD camera or the imaging tube based on the same type of plastic in the region of the CCD camera or the imaging tube where the reflected light from each plastic in the near-infrared irradiation region of the mixture enters through the three or more types of bandpass filters. The amount of reflected light in the area was compared with each other, and the material of the plastic in the mixture was identified from the difference between the reflected light amounts. It is characterized in that of comprising an identification means.

[0009] A plastic material identification / separation system according to the present invention comprises a conveying means for conveying a mixed substance containing a plurality of types of plastics, and a system for irradiating the mixed substance conveyed by the conveying means with near-infrared rays. Irradiating means, an imaging member including a CCD camera or an image pickup tube each having three or more types of bandpass filters having different wavelengths at which reflected light from the mixture irradiated with near-infrared rays is incident; In the area of the CCD camera or the image pickup tube where the reflected light from each plastic in the infrared irradiation area is incident through the three or more kinds of bandpass filters, the reflection in the area of the CCD camera or the image pickup tube based on the same kind of plastics An identifying means for comparing the light amounts with each other and identifying the plastic material in the mixture from the difference in the reflected light amounts. When and it is characterized by comprising a separating means for separating a predetermined plastic on the basis of the identification means.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A plastic material identification / separation system including a plastic material identification system according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic diagram of a plastic identification / separation system.

Conveying means for conveying a mixture containing a plurality of types of plastics, for example, a metal belt conveyor 1
Is moved in the direction of the arrow. For example, the two visible lamps 2a and 2b are arranged above the belt conveyor 1 at a desired distance from each other in the surface direction of the belt conveyor 1. Visible camera, for example, visible CCD camera 3
Are located above the belt conveyor 1 above the light sources 2a, 2b.
It is arranged so as to be located between them.

For example, two infrared lamps 4a and 4b are arranged above the belt conveyor 1 so as to be adjacent to the visible CCD camera 3 and the moving direction of the belt conveyor 1. The housing 6 is arranged above the bell conveyor 1 so as to be located between the infrared lamps 4a and 4b. Three or more types, for example, first to third bandpass filters 7 ₁ , 7 ₂ , and 7 ₃ are housed in the housing 6. For example, when plastics are classified into polyethylene terephthalate, polystyrene, and other three types, the first bandpass filter 71 is _one that transmits only the incident light having a wavelength near or near the absorption peak of polyethylene terephthalate. Used. As the second band-pass filter 7 _2, which transmits only incident light having a wavelength of absorption peak or in the vicinity thereof of polystyrene is used. Examples of the third band-pass filter 7 _3, which transmits only incident light having a wavelength of absorption peak or near the polyethylene terephthalate and plastics other than polystyrene can be used.

More specifically, 1100 to 12 shown in FIG.
When the absorption band of 60 nm is used, the first bandpass filter 7 is used based on the relationship between the wavelength and the absorbance of various plastics.
₁ is a wavelength of 1123～1133Nm, wavelength of the second band-pass filter 7 ₂ from 1137 to 1147, the third band-pass filter 7 ₃ is used as it transmits wavelengths 1190～1200Nm, only incident light. In the case of using the absorption band of 1600~1800nm Figure 3 shows the wavelength from the relationship between the wavelength and the absorbance first band-pass filter ₇₁ is the 1650~1660nm of various plastics, the second band-pass filter 7 ₂ Is 1670-1680
Wavelength, the third band-pass filter 7 ₃ 1720-17
One that transmits only incident light having a wavelength of 30 nm is used. Transmission wavelength of such first to third band-pass filter 7 _1, 7 _2, 7 _3, may be selected by identifying the type of plastic and object to be identified.

A first to third camera of the image pickup tube type (for example, trade name: C2741-03, manufactured by Hamamatsu Photonics KK) 8 ₁
8 to 8 ₃ are arranged in the housing 6 in close proximity to the upper surfaces of the band-pass filters 7 ₁ , 7 ₂ , 7 ₃ . These _first to _third cameras 81 to 83 are, for example, 800 to 19
It has sensitivity up to the near infrared region of 00 nm. However, a CCD camera having sensitivity up to the near-infrared region may be used instead of the camera of the image pickup tube type.

When there are many types of plastics to be identified, four or more bandpass filters and a camera corresponding thereto may be used.

The visible CCD camera 3 and first to third
Camera 8 _{1-8 3} camera tube type are connected to the image processing apparatus 9. The image processing device 9 is transported by the belt conveyor 1 and receives the visible lamps 2a,
From 2b, a visible image of a mixture of various plastics irradiated with visible light is input.

The image processing device 9 has an image pickup tube tie.
First to third cameras 8₁~ 8_ThreeVideo from each
Is entered. That is, the sheet is conveyed by the belt conveyor 1.
And infrared light was emitted from the infrared lamps 4a and 4b.
The reflected light reflected by the mixture of various plastics is the first
~ 3rd band pass filter 7₁, 7_Two, 7_ThreeIncident on
And these filters 7₁, 7_Two, 7_ThreeThrough the said
First to third cameras 8₁~ 8 _ThreeIs incident on. These turtles
La 8₁~ 8_ThreeThe three images projected by the above-mentioned image processing
Output to the device 9 respectively. In this image processing device 9,
Is the same in a specific visual field region among the respective image data.
Difference in lightness and darkness related to the amount of reflected light in plastics etc.
Are compared, and whether the difference exceeds the threshold or not
Identify the plastic material.

More specifically, when a mixture of various plastics is irradiated with infrared light from the infrared lamps 4a and 4b, wavelengths corresponding to the absorption spectra of the various plastics are absorbed. For example, for polyethylene terephthalate, 16
Wavelengths around 55 nm are most absorbed. For this reason, the first type of the image pickup tube type in which the reflected light of polyethylene terephthalate enters through a band-pass filter (for example, the first band-pass filter 7 ₁ ) transmitting a wavelength of 1655 nm.
In the camera ₈₁ reflected light amount is small, that is, dark image. On the other hand, the second and third imaging tube types in which the reflected light is incident through a band-pass filter (for example, second and third band-pass filters 7 ₂ and 7 ₃ ) other than a band-pass filter that transmits a wavelength of 1655 nm. The cameras 8 ₂ and 8 ₃ have a large amount of reflected light, that is, a bright image. As a result, the image processing apparatus 9, based on the polyethylene terephthalate in the amount of reflected light (dark images) from the first camera _81, second, third camera 8 _2, polyethylene terephthalate in the amount of reflected light from 8 ₃ ( By comparing the difference in the amount of reflected light (brightness difference) with that of a bright image, the plastic is identified as polyethylene terephthalate in order to obtain a difference in brightness sufficient to exceed the threshold value.

The microwave transmitting antenna 10 is disposed above the belt conveyor 1 so as to be adjacent to the infrared lamp 4b in the moving direction of the belt conveyor 1. The plurality of rod-type receiving antennas 11 are arranged below the belt conveyor 1 so as to face the transmitting antenna 10. The microwave control device 12 is connected to the transmitting antenna 10 and outputs a signal for controlling the microwave from the transmitting antenna 10. Also,
The microwave control device 12 is connected to the reception antenna 11, and receives the reception signal.

The system control device 13 is connected to the image processing device 9 and the microwave control device 12, and receives processing signals from the devices 9, 12, respectively.

The sorting device 14 is arranged so as to be positioned in the moving direction of the belt conveyor 1 with respect to the microwave transmitting antenna 10 and, for example, for separating a specific plastic from the mixture of the belt conveyor 1. three robots (the first to third robot) 15 _{1-15 3,} these first to third robot 15 _{1-15 3} first to third for recovering fractionated plastic by the recovery box 16
And a _{1-16 3.}

The _first to third robots 15 ₁ to 15
Numerals ₃ are arranged so as to straddle the belt conveyor 1 and support a U-shaped support arm 17 movable in the width direction of the conveyor 1 and a gripping mechanism attached to the lower surface at the center of the support arm 17. And a gripping mechanism 19 attached to the lower end of the support rod 18. This gripping mechanism 19
As shown in FIG. 4, a disk-shaped main body 20 attached to the support rod 18, for example, six guide rails 21 extending radially from the side surface of the main body 20, and along each of the guide rails 21 by air pressure, for example. Six fingers 22 for reciprocating and gripping the plastic conveyed on the belt conveyor 1, and these fingers 22
And a compressed air supply source (not shown) for supplying compressed air through a hose (not shown) to the driving portion of the motor. In such first to third robot 15 _{1-15 3,} the support arm 17, support rod 18 and the gripping mechanism 19 is driven by a control signal from the system controller 13, for example, the first robot 15 ₁ the fractionated polyethylene terephthalate (PET), the second robot 15 ₂ is fractionated polystyrene (PS), the third robot 15 ₃ functions as a dedicated machine for separating PET, a plastic other than PS.

Next, identification and identification of the plastic according to the present invention will be described.
The sorting apparatus will be described with reference to FIGS. 1, 4, 5 and 6 described above.

First, a mixture 2 containing various plastics
3 is irregularly supplied to a metal belt conveyor 1 and transported. Visible light is emitted from the two visible lamps 2a and 2b to the mixture 23, and the mixture is imaged by the visible CCD camera 3.
As the image data D ₀ is outputted to the image processing apparatus 9, the shape of various plastics such as inclusions 23 of the camera 3 within the field of view are identified as shown in.

The mixture 23 is irradiated with infrared light from the infrared lamps 4a and 4b, and reflected light from various plastics is passed through a first band-pass filter 7 ₁ (transmitting a wavelength of 1655 nm). 1 imaged by the imaging tube type camera 8 _1, and outputs the image data D ₁ to the image processing device 9. The same reflected light is applied to the second bandpass filter 7 ₂ (16
Captured by the camera 8 of the _second image pickup tube type through transmission wavelength of 75 nm), the image processing apparatus the image data D ₂ 9
Output to A similar reflected light is passed through a third bandpass filter 7.
₃ captured by the camera 8 of the _third image pickup tube type through (transmitted through a wavelength of 1722 nm), and outputs the image data D ₃ to the image processing apparatus 9.

In such an image processing apparatus 9,
Tube type first camera 8₁Is the absorption wavelength peak of PET
First bandpass filter transmitting a certain wavelength of 1655 nm
Ruta 7₁The reflected light is incident upon passing through
Camera 8₁Of the image data D1 captured at
At the place where the reflected light was imaged, a dark image 24₁Becomes
On the other hand, second and third cameras 8 of the image pickup tube type_Two, 8_ThreeHaso
PS and PET and plastics other than PS, respectively.
Wavelengths of 1675 nm and 1722 nm which are light wavelength peaks
And third bandpass filters 7 that transmit light_Two, 7_ThreeTo
Since the reflected light passes through the second and third light sources,
Camera 8_Two, 8_ThreeImage data D captured at_Two, D_ThreeHorse
In other words, the location where the reflected light from PET is imaged is relatively bright.
Video 24 _Two, 24_ThreeBecomes As a result, the image processing device
First image data D₁Dark picture 24 of₁Based on
And the second and third image data D_Two, D_ThreeBright picture of
24_Two, 24_ThreeIf you compare the difference in brightness between
Plastics to obtain a sufficient contrast
The lock is identified as PET.

In the image processing apparatus 9, the image pickup tube tie
Second camera 8_TwoIs the absorption wavelength peak of PS 16
Second bandpass filter 7 transmitting 75 nm wavelength_Two
And the reflected light is incident on the second camera 8
_TwoImage data D captured at_TwoOf the reflected light from the PS
Dark image 25 at the place where_TwoBecomes Meanwhile, imaging
First and third tube type cameras 8₁, 8_ThreeIs PE
Absorption wavelength of plastics other than T, PET and PS
Transmitting wavelengths of 1655 nm and 1722 nm
First and third bandpass filters 7₁, 7_ThreeThrough
Since the reflected light is incident, these first and third cameras
8₁, 8_ThreeImage data D captured at₁, D_ThreeOf which, PS
A relatively bright image 25 where the reflected light from
₁, 25 _ThreeBecomes As a result, the image processing device 9
And the second image data D_TwoDark picture 25_TwoBased on
1. Third image data D₁, D_ThreeBright picture 25₁, 2
5 _ThreeComparing the difference in brightness between
The plastic is made of PS
Identified as

In the image processing apparatus 9, the image pickup tube tie
Third camera 8_ThreeIs plastic other than PET and PS
(Eg, polypropylene; PP).
Third bandpass fill transmitting 1722 nm wavelength
TA7_ThreeThe reflected light is incident through the
Mela 8_ThreeImage data D captured at_ThreeOf which, from PP
Dark image 26 at the place where the reflected light was imaged_ThreeBecomes one
The first and second cameras 8 of the image pickup tube type₁, 8_TwoIs it
1655, which is the absorption wavelength peak of PET and PS, respectively.
nm and 1675 nm transmitting the wavelength of 1675 nm.
Dopass filter 7 ₁, 7_TwoAnd the reflected light is incident
Therefore, these first and second cameras 8₁, 8_TwoImaged at
Image data D₁, D_TwoOf reflected light from PP
Relatively bright picture 26₁, 26_TwoBecomes So
As a result, the third image data D
_ThreeDark picture 26_ThreeBased on the first and second image data
TA D₁, D_TwoBright picture 26₁, 26_TwoAnd the difference in brightness
By comparison, there is a sufficient intensity difference to exceed the threshold
The plastic is identified, for example, as PP
You.

Further, in the image processing apparatus 9, the first
Image data D ₁ inputted from to third camera 8 _{1-8 3}
Of to D _3, all bright image 27 _{1-27 3} wherein PE
T, PS, other plastics (eg, PP, P
Materials not falling under any of E) (eg, metals)
Identified as

When the mixture 23 passes below the _first to _third cameras 81 to 83 by the belt conveyor 1 and reaches below the transmitting antenna 10, the transmitting antenna 10 outputs a frequency of 2.45 GHz, for example. Is radiated to the mixture 23, and the transmitted microwaves are detected by the plurality of rod-type receiving antennas 11 below the belt conveyor 1, and the detection data (moisture information; information on the moisture adhesion area and moisture amount)
Is the system controller 1 through the microwave controller 12
3 is output. The system control device 13 includes, in addition to the material identification data of the image processing device 9,
PET bottle 24, PS tray 25, PP container 2 shown in
Since visible image data of, for example, a metal piece 27 other than the plastic 6 and the metal piece 27 is input, the state of the dirt and the remaining liquid 28 is determined from the visible image and the moisture information as shown in FIG. Display on plastic (for example, display that PS tray 25 and PP container 26 are dirty)
I do. From this result, it is determined that the PS tray 25 and the PP container 26 cannot be recycled as shown in FIG.

[0032] In such a system controller 13, the first to third robot 15 _{1-15 3} fractionation device 14 on the basis of the material identifying data and the recycle not data input from the image processing device 9 is driven Predetermined plastics, especially recyclable specific plastics, in the mixture 23 conveyed by the bell conveyor 1 are separated and collected. That is, when the material is identified by the inclusions 23 in the visual field shown in FIGS. 5 and 6 described above, and the recyclable plastic is determined to be the PET bottle 24, the drive signal from the system control device 13 is set to the first signal.
Is output to the robot 15 _1, the first robot 15 ₁ of the support arm 17 is moved to the gripping mechanism 19 of the support rod 18 the lower end is located immediately above the PET bottles on the belt conveyor 1, the support rod 18 6 of the descending and holding mechanism 19
The PET bottle is gripped by the independent horizontal movement of the two fingers 22. Gripped PET bottle, the movement of the support arm 17 is collected in a first collection box 16 ₁ by the gripping releasing operation of the six fingers 22 of the gripping mechanism 19.

As described above, according to the present invention, the belt conveyor 1 for conveying the mixture 23 containing plural kinds of plastics.
And the infrared lamps 4a and 4b for irradiating near-infrared light to the mixture 23 conveyed by the conveyor 1, and the wavelength at which reflected light from the mixture 23 irradiated with near-infrared light is different. An imaging member (for example, an imaging tube type first to third imaging device) including a CCD camera or an imaging tube having three or more types of bandpass filters (for example, first to third bandpass filters 7 ₁ , 7 ₂ , 7 ₃ ). of the camera 8 ₁
8 ₃ ), and the first to third band-pass filters 7 ₁ , 7 ₂ , 7 _{3 in which} the reflected light from each plastic in the near-infrared irradiation area of the mixture 23 is incident.
Third camera 8 _1-8 of the _three areas, the mix from their reflected light amount difference the first to third camera 8 _{1-8 3} reflected light amount in the area of which is based on plastic of the same type as compared with one another By providing identification means for identifying the material of the plastic in the object, even if the mixture 23 containing a plurality of kinds of plastics is randomly supplied to the belt conveyor 1 and transported, the plastic in the mixture is , For example, PET, PS, and other plastics can be identified. As a result, an alignment device for aligning various plastics on the belt conveyor becomes unnecessary, and a low-cost material identification system can be realized. Moreover,
The throughput of the identified plastic can be increased.

Further, if a visual camera, for example, a visible CCD camera 3 is arranged above the belt conveyor 1 together with the visible lamps 2a and 2b and the mixed object 23 conveyed by the bell conveyor 1 is imaged, the mixed object 23 within the specific visual field can be obtained. Plastic shapes in objects can also be identified. As a result, the separation accuracy of the recyclable plastic in the subsequent separation can be further improved.

Further, if residues such as moisture and dirt of the mixture 23 on the belt conveyor 1 are detected by detecting means such as the transmitting antenna 10 and the plurality of rod-type receiving antennas 11, for example, It can be used as information for determining whether recycling is possible.

Further, the _first to _third robots 15 ₁ to 15 ₃ and the _first to _third robots 15 ₁ to 15 ₃ are moved in the moving direction of the mixture from various members which take in the material identification data and the recyclability data.
By the third fractionation unit 14 is arranged with a collection box 16 ₁ to 16 _3, and drives based on the sorting apparatus 14 in the material identifying data input to the system controller 13,
Predetermined plastics in the mixture 23 in which various plastics and the like are mixed can be separated and collected. In particular, and by taking the recyclability data in the system control device 13 as the separation operation information of the separation device 14, specific plastics that can be recycled can be separated and collected.

In the above-described embodiment, the predetermined plastic in the mixture is automatically separated by the separation device. However, as shown in FIG. 1, the material identification data and the recyclability data inputted to the system controller 13 are monitored. 2
9 may be displayed as an image, and based on the image from the monitor 29, the operator may sort out a specific plastic in the mixture flowing on the belt conveyor 1.

[0038]

As described above in detail, according to the present invention, even if a mixture containing a plurality of types of plastics is transported without being aligned on the transporting means, the material of the plastics can be identified, and the alignment device can be omitted. Accordingly, it is possible to provide a plastic material identification system capable of realizing cost reduction and further increasing the amount of plastic to be identified.

Further, according to the present invention, the material of the plastic can be identified and the specific plastic can be automatically separated even if the mixed material containing a plurality of types of plastics is transported without being arranged on the transporting means. It is possible to provide a low-cost, mass-processable plastic material identification / separation system useful for recycling.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a plastic material identification / separation system according to the present invention.

FIG. 2 is a characteristic diagram showing the relationship between the wavelength and the absorbance of various plastics.

FIG. 3 is a characteristic diagram showing the relationship between wavelength and absorbance of various plastics.

FIG. 4 is a front view showing a gripping mechanism of the sorting device incorporated in the system of FIG. 1;

FIG. 5 is a diagram for explaining an operation of identifying various plastics in a mixture by the system of FIG. 1;

FIG. 6 is a diagram for explaining whether or not recycling of various plastics in a mixture is permitted by the system of FIG. 1;

[Explanation of symbols]

1 ... belt conveyor, 2a, 2b ... visible light, 3 ... visible CCD, 4a, 4b ... infrared lamp, 7 _1, 7 _2, 7 ₃ ... bandpass filter 8 _{1-8 3} ... imaging type camera, 9 ... image processing apparatus, 10 ... transmitting antenna, 11 ... receiving antenna, 12 ... microwave controller 13 ... system controller, 14 ... fractionator, 15 _{1-15 3} ... robot, _{161-164 3} ... collection box, 23 ... mixture.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G01N 22/04 G01N 22/04 Z (72) Inventor Yasuhiro Sueoka 1-8-1, Koura, Kanazawa-ku, Yokohama-shi, Kanagawa 1 Mitsubishi Heavy Industries, Ltd. Yokohama Laboratory (72) Inventor Ayumu Yamazaki 12th Nishikicho, Naka-ku, Yokohama-shi, Kanagawa Prefecture Mitsubishi Heavy Industries, Ltd. Yokohama Works F-term (reference) 2G059 AA05 BB08 DD11 DD12 EE02 EE11 EE12 FF01 GG03 HH01 HH02 HH06 JJ02 KK04 MM01 MM05 MM09 PP04 3F079 AD11 CA31 CA45 CB25 CB30 CB33 CB34 CC01 DA12

Claims (6)

[Claims] 1. A conveying means for conveying a mixture containing a plurality of types of plastics; an irradiating means for irradiating near-infrared light to the mixture conveyed by the conveyance means; An imaging member including a CCD camera or an image pickup tube having three or more types of bandpass filters having different wavelengths at which reflected light from the inclusion is incident; and reflection light from each plastic in a near-infrared irradiation region of the inclusion. Are compared with each other in the area of the CCD camera or the image pickup tube based on the same type of plastic, among the areas of the CCD camera or the image pickup tube which are incident through the three or more types of band-pass filters, and the difference between the reflected light amounts is obtained. And identification means for identifying the material of the plastic in the mixture. Another system. 2. The three or more kinds of band-pass filters, wherein a first band-pass filter transmits light having a wavelength near or near an absorption peak of polyethylene terephthalate, and a second band-pass filter has a light absorption peak of polystyrene. 2. The light-transmitting device according to claim 1, wherein light having a wavelength in the vicinity thereof is transmitted, and said third band-pass filter transmits light having a wavelength near or near the absorption peak of plastics other than polyethylene terephthalate and polystyrene. Plastic material identification system. 3. The plastic material identification system according to claim 1, further comprising a visible camera for determining the shape of the plastic in the mixture on the conveying means. 4. The plastic material identification system according to claim 1, further comprising a detecting unit for detecting a residue of the mixed substance on the transporting unit. 5. A conveying means for conveying a mixture containing a plurality of types of plastics, an irradiation means for irradiating the mixture conveyed by the conveyance means with near-infrared light, and An imaging member including a CCD camera or an image pickup tube having three or more types of bandpass filters having different wavelengths at which reflected light from the inclusion is incident; and reflection light from each plastic in a near-infrared irradiation region of the inclusion. Are compared with each other in the area of the CCD camera or the image pickup tube based on the same type of plastic, among the areas of the CCD camera or the image pickup tube which are incident through the three or more types of band-pass filters, and the difference between the reflected light amounts is obtained. Identification means for identifying the material of the plastic in the mixture from, a predetermined plastic based on the identification means Material identifying and sorting system of the plastic, characterized by comprising a separating means for separate. 6. A control device connected to the identification device for inputting material information of the plastic of the mixture, and a sorting device configured to horizontally move the upper part of the transporting device based on information from the control device. 6. A plastic material identification / separation system according to claim 5, further comprising: a robot that is movable in a vertical direction and moves a gripping member for gripping the plastic in a vertical direction.