CN114354531B - Plastic identification system of dual-wavelength coherent light source based on near infrared - Google Patents
Plastic identification system of dual-wavelength coherent light source based on near infrared Download PDFInfo
- Publication number
- CN114354531B CN114354531B CN202111648368.5A CN202111648368A CN114354531B CN 114354531 B CN114354531 B CN 114354531B CN 202111648368 A CN202111648368 A CN 202111648368A CN 114354531 B CN114354531 B CN 114354531B
- Authority
- CN
- China
- Prior art keywords
- light
- plastic
- wavelength
- sample
- unit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 229920003023 plastic Polymers 0.000 title claims abstract description 101
- 239000004033 plastic Substances 0.000 title claims abstract description 101
- 230000001427 coherent effect Effects 0.000 title claims abstract description 14
- 230000003287 optical effect Effects 0.000 claims abstract description 40
- 239000013078 crystal Substances 0.000 claims abstract description 31
- 238000001514 detection method Methods 0.000 claims abstract description 27
- 238000005086 pumping Methods 0.000 claims abstract description 17
- 230000008878 coupling Effects 0.000 claims description 39
- 238000010168 coupling process Methods 0.000 claims description 39
- 238000005859 coupling reaction Methods 0.000 claims description 39
- 230000009977 dual effect Effects 0.000 claims description 11
- 230000000737 periodic effect Effects 0.000 claims description 10
- 238000002834 transmittance Methods 0.000 claims description 10
- 238000002310 reflectometry Methods 0.000 claims description 9
- 238000006243 chemical reaction Methods 0.000 claims description 5
- 230000009471 action Effects 0.000 claims description 4
- 230000001678 irradiating effect Effects 0.000 claims description 3
- 238000002922 simulated annealing Methods 0.000 abstract description 6
- 238000013461 design Methods 0.000 abstract description 3
- 239000000463 material Substances 0.000 abstract description 3
- 238000001228 spectrum Methods 0.000 description 7
- 238000002329 infrared spectrum Methods 0.000 description 5
- 230000003595 spectral effect Effects 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 4
- 230000003321 amplification Effects 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 238000003199 nucleic acid amplification method Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 229910000530 Gallium indium arsenide Inorganic materials 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000000295 emission spectrum Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000005286 illumination Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000011897 real-time detection Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 230000002269 spontaneous effect Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Landscapes
- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
The invention discloses a plastic identification system based on a near infrared dual-wavelength coherent light source, which is characterized in that a light source unit designs an aperiodic polarized crystal based on a quasi-phase matching principle by using a simulated annealing algorithm, and the aperiodic polarized crystal outputs dual-wavelength laser signals with the wavelengths of 1662nm and 1716nm under a pumping source and an optical parametric oscillator; the sample collecting unit divides the reflected light of the tested plastic sample into two lights with the wavelengths of 1662nm and 1716nm through the optical filter; the detection unit converts the two lights into photocurrent signals, the recognition unit amplifies the photocurrent signals, and the plastic type of the tested plastic sample is determined according to the size ratio of the two lights with the wavelengths of 1662nm and 1716nm, and the recognition system can rapidly and accurately recognize PET, PVC, PS plastic materials.
Description
Technical Field
The invention relates to the technical field of plastic identification, in particular to a plastic identification system of a near infrared-based dual-wavelength coherent light source.
Background
The plastic identification device mainly based on near infrared spectrum analysis in the prior art generally comprises a power supply unit, a sample acquisition unit, a detection unit and a circuit control unit, wherein the light source unit is used for providing a light source; the sample collecting unit is used for collecting reflected light of the sample to be identified and transmitting the reflected light to the detecting unit; the detection unit is used for splitting the reflected light and converting the split reflected light into a photocurrent signal to be transmitted to the circuit control unit; the circuit control unit comprises a direct-current power supply, an operational amplifier and a computer control end; the operational amplifier is used for receiving the photocurrent signal, amplifying the photocurrent signal and transmitting the amplified photocurrent signal to the computer control end, and processing and identifying the optical data are realized at the computer end.
The existing plastic identification and detection device based on the near infrared spectrum technology mainly comprises two main types: one is the use of a portable spectrometer, which is relatively costly, and the other is the use of a spectral sensor or photodiode. The two major types of identification systems mainly use a white light source as an illumination light source of the system, and a portable spectrometer can directly acquire the reflection spectrum of a measured plastic sample to realize type identification on a computer, but the identification speed is too slow to realize real-time measurement of the system; when the spectrum sensor is used for detection, the spectrum sensor mainly uses electric control to split light, and the sensor is sensitive to temperature and the temperature, so that the detected spectrum is easy to deviate to cause identification errors; when the photodiode is used for direct measurement, at least two spectral data at specific wavelength positions are needed to be obtained for identification, and because the wavelength range of light emitted by the white light source is wide, in order to obtain pure spectral information at a certain wavelength, two narrow-bandwidth optical filters with different center wavelengths are needed to be used for light splitting, and the manufacturing difficulty and the manufacturing cost of the narrow-bandwidth optical filters with specific wavelengths are high.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention provides a plastic identification system based on a near infrared dual-wavelength coherent light source, which solves a series of problems that a traditional spectrometer cannot realize rapid and real-time identification of a plastic sample in a plastic identification process, a spectrum sensor is greatly influenced by environmental temperature, a narrow bandwidth optical filter with special wavelength is difficult to manufacture and the like.
In order to achieve the above purpose, the present invention adopts the following technical scheme, including:
a near infrared based plastic identification system for a dual wavelength coherent light source, comprising: the device comprises a light source unit, a sample acquisition unit, a detection unit and an identification unit;
the light source unit is used for generating two double-signal lights with different wavelengths and irradiating the double-signal lights on the tested plastic sample; after the double-signal light irradiates the tested plastic sample, the tested plastic sample generates reflected light, and the sample collecting unit is used for collecting the reflected light of the tested plastic sample and dividing the reflected light of the tested plastic sample into two lights which respectively correspond to the two different wavelengths, namely, first wavelength light and second wavelength light; the sample collection unit is connected with the detection unit and transmits light with two different wavelengths to the detection unit; the detection unit is used for respectively carrying out photoelectric conversion on light with two different wavelengths and converting the light into two photocurrent signals; the detection unit is connected with the identification unit, and is used for sending two photocurrent signals to the identification unit, the identification unit is used for converting the two photocurrent signals into two digital signals, and the plastic type of the tested plastic sample is identified according to the ratio of the two digital signals.
The light source unit includes: the device comprises a laser, an optical coupling lens group, an input coupling mirror, an aperiodic polarized crystal and an output coupling mirror;
the laser is used as a pumping source to output pumping light; the pumping light output by the laser sequentially passes through the optical coupling lens and the input coupling lens, and is focused to the central position of the non-periodic polarized crystal, and the non-periodic polarized crystal generates two double-signal lights with different wavelengths through the optical parametric oscillator under the action of the pumping light, and the double-signal lights are output through the output coupling lens and irradiate on a tested plastic sample;
the optical resonant cavity of the optical parametric oscillator consists of an input coupling mirror and an output coupling mirror; the input coupling mirror transmits the wave band of the pump light and reflects the two wave bands of the double-signal light; the output coupling mirror transmits two wave bands of the double-signal light and reflects the wave bands of the pump light;
the two ends of the non-periodic polarized crystal are plated with high-transmittance films which are respectively high in transmittance to the wave band of the pump light and the two wave bands of the double-signal light.
The non-periodically poled crystals are placed in a temperature controlled oven.
The sample collection unit comprises a light filter, and the light filter divides the reflected light of the tested plastic sample into two lights which respectively correspond to the two different wavelengths, namely, first wavelength light and second wavelength light.
The detection unit comprises a first photodiode and a second photodiode, wherein the first photodiode and the second photodiode respectively carry out photoelectric conversion on light with two different wavelengths and convert the light into two photocurrent signals.
The identification unit includes: the device comprises a first transimpedance amplifier, a second transimpedance amplifier and a singlechip, wherein the first transimpedance amplifier and the second transimpedance amplifier respectively convert two photocurrent signals into voltage signals and amplify the voltage signals to obtain two amplified voltage signals; the first transimpedance amplifier and the second transimpedance amplifier respectively send two amplified voltage signals to the singlechip; the singlechip converts the two amplified voltage signals into two digital signals, calculates the ratio between the two digital signals, and identifies the plastic type of the tested plastic sample according to the ratio.
Two different wavelengths of the dual signal light generated by the light source unit are 1662nm and 1716nm respectively; the first wavelength light separated by the optical filter is light with the wavelength of 1662nm, and the second wavelength light is light with the wavelength of 1716nm; the plastic categories include: PVC, PET, PS.
The digital signal converted based on light with the wavelength of 1662nm is a first digital signal, the digital signal converted based on light with the wavelength of 1716nm is a second digital signal, the ratio between the first digital signal and the second digital signal is R, and if R is 0.8> 0.7, the plastic type of the tested plastic sample is PET; if 1> R >0.9, the plastic type of the tested plastic sample is PS; if R >1.5, the plastic type of the tested plastic sample is PVC.
The transmittance of the input coupling mirror to the wave band of the pump light is higher than 95%; the reflectivity of the input coupling mirror to two wave bands of the double-signal light is higher than 99%; the transmittance of the output coupling mirror to two wave bands of the double-signal light is higher than 87%, and the reflectivity to the wave band of the pump light is higher than 86%.
The invention has the advantages that:
(1) For the same plastic under different conditions, for example, when the thickness of the plastic sample is different, the absolute reflection is changed along with the thickness of the plastic sample, and the ratio of the reflectivities at two wavelengths, namely the relative reflectivities, is irrelevant to the thickness of the plastic sample.
(2) The light source unit designs an aperiodic polarized crystal by using a simulated annealing algorithm based on a quasi-phase matching principle, and the aperiodic polarized crystal outputs dual-wavelength laser signals with the wavelengths of 1662nm and 1716nm under a pumping source and an optical parametric oscillator; the sample collecting unit divides the reflected light of the tested plastic sample into two lights with the wavelengths of 1662nm and 1716nm through the optical filter; the subsequent use wavelength is 1662nm and 1716nm two light size ratio, to determine the plastic sample of the plastic category, the identification system can rapidly and accurately identify PET, PVC, PS three materials plastic.
(3) According to the invention, the effect of light splitting can be realized by using only one optical filter, the obtained dual wavelength is not limited by the laser emission spectrum line, tuning in a fixed range can be realized by means of crystal rotation and the like, and the optical filter has great flexibility; the selection range of the dual wavelength to the filter plate is larger, and a common short-wave dichroic filter with simple manufacture can be used; the laser has the characteristics of good monochromaticity, directivity and coherence, so that the obtained optical signal is purer, and the accuracy of measurement is improved. The method is rapid and simple in plastic identification, good in identification of common plastics (PVC, PET, PS) and capable of realizing real-time detection.
(4) The invention selects the light with the characteristic wavelength of the plastic in the near infrared spectrum range to irradiate the tested plastic sample, wherein the light with the characteristic wavelength of the PVC and the PET in the near infrared spectrum range, namely 1662nm and 1716nm, is selected to irradiate the tested plastic sample, and the wavelength selection can rapidly and accurately distinguish PVC, PET, PS plastics.
Drawings
FIG. 1 is a block diagram of a plastic identification system according to the present invention.
Fig. 2 is a block diagram of the plastic identification system of the present invention.
FIG. 3 is a graph of the wavelength of light output by an aperiodic polarized crystal versus the amplification factor.
Fig. 4 is a spectral plot of PVC, PET, PS.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
As shown in fig. 1, the plastic identification system based on the near infrared dual-wavelength coherent light source mainly comprises: a light source unit A, a sample acquisition unit B, a detection unit C and a recognition unit D.
The light source unit A is based on a quasi-phase matching principle, utilizes a simulated annealing algorithm to design an aperiodic polarized crystal, and outputs dual-wavelength laser signals with the wavelengths of 1662nm and 1716nm under an optical parametric oscillator consisting of a pumping source with the output wavelength of 1064nm and an optical resonant cavity, so as to provide a light source for a plastic identification system; the sample collection unit B is mainly used for collecting reflected light of a tested plastic sample, divides the reflected light into two lights with wavelengths of 1662nm and 1716nm through an optical filter, and transmits the two lights to the detection unit C; the detection unit C is mainly used for converting two lights with wavelengths of 1662nm and 1716nm into two photocurrent signals and transmitting the two photocurrent signals to the identification unit D; the identification unit D comprises an operational amplifier and a singlechip; the operational amplifier is used for receiving the two photocurrent signals, amplifying the photocurrent signals and transmitting the amplified photocurrent signals to the singlechip for identification; the single chip microcomputer end determines the plastic type of the tested plastic sample through the size ratio of two lights with the wavelength of 1662nm and 1716nm, and the identification system can rapidly and accurately identify PET, PVC, PS plastic materials.
The plastic identification types of the system mainly comprise three types: PVC, PET, PS; wherein, the characteristic wavelengths of PVC and PET in the near infrared spectrum range are respectively at 1662nm and 1716nm, the spectrum has obvious change at the characteristic wavelength, and the spectrum curve of PVC, PET, PS is shown in FIG. 4.
For the same plastic under different conditions, such as different thicknesses of the plastic sample, the absolute reflectivity varies with the thickness of the plastic sample, while the relative reflectivity, i.e., the ratio of the reflectivities at the two wavelengths, i.e., the relative reflectivity, is independent of the thickness of the plastic sample. Therefore, the reflected light values at two wavelengths are selected for identification, and the identification accuracy of samples under different conditions is improved. As shown in FIG. 4, the wavelengths at the characteristic lines, i.e., the characteristic wavelengths, are chosen to have a strong contrast, the reflected light ratio values of 1662nm and 1716nm are significantly less than 1 for PET, the reflected light ratio values of 1662nm and 1716nm are significantly greater than 1 for PVC, and the reflected light ratio values of 1662nm and 1716nm are within a small range around 1 for PS. Therefore, the invention selects the light with the wavelength of 1662nm and 1716nm to irradiate the tested plastic sample, and the wavelength can be selected to well distinguish three types of plastics.
As shown in fig. 2, a plastic identification system based on a near infrared dual-wavelength coherent light source of the present embodiment mainly includes: a light source unit A, a sample acquisition unit B, a detection unit C and a recognition unit D.
The light source unit a is used for emitting a light source for irradiating a sample to be identified, namely a tested plastic sample 7.
The light source unit a includes: the laser comprises a laser 1, an optical coupling lens group 2, an input coupling mirror 3, a temperature control furnace 4, an aperiodic polarized crystal 5 and an output coupling mirror 6.
The laser 1 is used as a pumping source, a semiconductor laser which outputs light with the wavelength of 1064nm is adopted, the laser 1 outputs pumping light with the wavelength of 1064nm, then the pumping light sequentially enters the temperature control furnace 4 through the optical coupling lens 2 and the input coupling mirror 3, the non-periodic polarized crystal 5 is placed in the temperature control furnace 4, the pumping light is focused to the central position of the non-periodic polarized crystal 5 in the temperature control furnace 4, and the non-periodic polarized crystal 5 generates double signal light with the wavelengths of 1662nm and 1716nm through the optical parametric oscillator under the action of the pumping light with the wavelength of 1064nm, and the double signal light is output through the output coupling mirror 6 and irradiates the measured plastic sample 7.
The optical resonant cavity of the optical parametric oscillator (OP 0) consists of an input coupling mirror 3 and an output coupling mirror 6, and consists of a plane input coupling mirror 3 and a plane concave output coupling mirror 6 with the curvature radius of 100mm, wherein the input coupling mirror 3 is a plane mirror, and is high in transmittance for 95% of light with the wavelength of 1064nm, high in reflectance for 99% of double-signal light with the wavelengths of 1662nm and 1716nm, and the output coupling mirror 6 is a plane concave mirror with the curvature radius of 100mm, and is high in transmittance for only 87% of light with the wavelengths of 1662nm and 1716nm, and high in reflectance for 86% of light with the wavelength of pump light band, i.e. 1064 nm.
Based on the quasi-phase matching principle, a strong high-frequency laser radiation (pump light) and a weak low-frequency laser radiation signal (signal light) are simultaneously incident on a nonlinear crystal, the weak signal is amplified and a low-frequency idler frequency light is generated, for example, the nonlinear crystal is placed in an optical resonant cavity, and when the amplification gain of parameters is larger than the inherent loss and coupling loss in the cavity, continuous coherent light is obtained at the signal light and the idler frequency light respectively, which is an optical oscillator. When the nonlinear crystal meets the quasi-phase matching condition, the signal light output of the optical oscillator can be used as output light; the non-periodic polarized crystal meeting a plurality of quasi-phase matching conditions can be designed by using a simulated annealing algorithm, the method is to select the width of each electric domain as a fixed value, set an objective function to optimize the reverse sequence of spontaneous polarization of each electric domain by using the simulated annealing algorithm, and then realize the multi-wavelength output through a nonlinear crystal.
Based on the quasi-phase matching principle and by using a simulated annealing algorithm, the aperiodic polarized crystal 5 is designed, the aperiodic polarized crystal 5 is placed in the temperature control furnace 4, the working range of the temperature control furnace 4 is between room temperature and 200 ℃, and the two ends of the aperiodic polarized crystal 5 are plated with high-transmission films for the pumping light wave band and the dual-signal light wave band, namely, the high-transmission films can transmit light with the wavelengths of 1064nm, 1662nm and 1716 nm. The aperiodic polarized crystal 5 generates double signal light with the wavelength of 1662nm and 1716nm through the optical parametric oscillator under the action of 1064nm pump light, and the relation between the wavelength and the amplification factor of the light output by the aperiodic polarized crystal 5 is shown in figure 3.
After the dual signal light irradiates the measured plastic sample 7, the measured plastic sample 7 generates reflected light.
The sample collection unit B is used for collecting reflected light of the tested plastic sample 7.
The sample collection unit B comprises an optical filter 8, wherein the optical filter 8 is a common short-wave dichroic optical filter, and the central wavelength is 1700nm; the filter 8 is highly transparent to light less than 1700nm and highly reflective to light at wavelengths greater than 1700 nm. The reflected light of the plastic sample 7 is divided into two beams perpendicular to each other by the optical filter 8, namely, light of 1662nm wavelength, namely, light of a first wavelength and light of 1716nm wavelength, namely, light of a second wavelength.
The sample collection unit B is connected with the detection unit C, and the sample collection unit B sends light with the wavelength of 1662nm and light with the wavelength of 1716nm to the detection unit C, and the detection unit C is used for converting the light with the two different wavelengths into photocurrent signals.
The detection unit C comprises two photodiodes, namely a first photodiode 9 and a second photodiode 10, which are identical InGaAs PIN photodiodes, and the spectral response range of the two photodiodes is 900-2000 nm.
The light of 1662nm wavelength and the light of 1716nm wavelength outputted from the filter 8 are irradiated to the first photodiode 9 and the second photodiode 10, respectively. Wherein the first photodiode 9 is configured to receive light of 1662nm wavelength and convert an optical signal of 1662nm wavelength into a first photocurrent signal. The second photodiode 10 is configured to receive 1716nm light and convert the received 1716nm light signal into a second photocurrent signal.
The detection unit C is connected to the identification unit D, and the detection unit C transmits the converted photocurrent signal to the identification unit D.
The identification unit D includes: the first transimpedance amplifier 11, the second transimpedance amplifier 12 and the singlechip 13.
The first transimpedance amplifier 11 is configured to convert the first photocurrent signal converted by the first photodiode 9 into a voltage signal and amplify the voltage signal to obtain a first amplified voltage signal, and send the first amplified voltage signal to the singlechip 13, where the singlechip 13 converts the first amplified voltage signal into a first digital signal.
The second transimpedance amplifier 12 is configured to convert the second photocurrent signal converted by the second photodiode 10 into a voltage signal and amplify the voltage signal to obtain a second amplified voltage signal, and send the second amplified voltage signal to the singlechip 13, where the singlechip 13 converts the second amplified voltage signal into a second digital signal.
Wherein the first digital signal is converted based on light of 1662nm wavelength and the second digital signal is converted based on light of 1716nm wavelength.
The singlechip 13 calculates a ratio R between the first digital signal and the second digital signal, identifies the plastic type of the tested plastic sample 7 according to the ratio R, and outputs an identification result, wherein the specific mode is as follows:
if the ratio R meets the condition of 0.8> R >0.7, the plastic type of the tested plastic sample 7 is PET; if the ratio R meets the condition 1> R >0.9, the plastic type of the tested plastic sample 7 is PS; if the ratio R satisfies the condition R >1.5, the plastic type of the tested plastic sample 7 is PVC.
The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the present invention, and any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of the present invention.
Claims (5)
1. A plastic identification system based on a near infrared dual wavelength coherent light source, comprising: a light source unit (A), a sample acquisition unit (B), a detection unit (C) and an identification unit (D);
the light source unit (A) is used for generating two double-signal lights with different wavelengths and irradiating the double-signal lights on the tested plastic sample (7); after the double signal light irradiates the tested plastic sample (7), the tested plastic sample (7) generates reflected light, and the sample collecting unit (B) is used for collecting the reflected light of the tested plastic sample (7) and dividing the reflected light of the tested plastic sample (7) into two lights which respectively correspond to the two different wavelengths, namely, first wavelength light and second wavelength light; the sample collection unit (B) is connected with the detection unit (C) and transmits light with two different wavelengths to the detection unit (C); the detection unit (C) is used for respectively carrying out photoelectric conversion on light with two different wavelengths and converting the light into two photocurrent signals; the detection unit (C) is connected with the identification unit (D) and is used for sending two photocurrent signals to the identification unit (D), and the identification unit (D) is used for converting the two photocurrent signals into two digital signals and identifying the plastic type of the tested plastic sample (7) according to the ratio of the two digital signals;
the light source unit (A) includes: the device comprises a laser (1), an optical coupling lens group (2), an input coupling mirror (3), an aperiodic polarized crystal (5) and an output coupling mirror (6);
the laser (1) is used as a pumping source and outputs pumping light; the pumping light output by the laser (1) sequentially passes through the optical coupling lens group (2) and the input coupling mirror (3) and is focused to the central position of the non-periodic polarized crystal (5), the non-periodic polarized crystal (5) generates two double-signal lights with different wavelengths through the optical parametric oscillator under the action of the pumping light, and the double-signal lights are output through the output coupling mirror (6) and irradiate on a tested plastic sample (7);
the optical resonant cavity of the optical parametric oscillator consists of an input coupling mirror (3) and an output coupling mirror (6); the input coupling mirror (3) transmits the wave band of the pump light and reflects two wave bands of the double-signal light; the output coupling mirror (6) transmits two wave bands of the double-signal light and reflects the wave band of the pump light;
both ends of the non-periodic polarized crystal (5) are plated with high-transmittance films which respectively have high transmittance to the wave band of the pump light and the two wave bands of the double signal light;
the sample collection unit (B) comprises a light filter (8), and the light filter (8) divides the reflected light of the tested plastic sample (7) into two lights which respectively correspond to the two different wavelengths, namely, first wavelength light and second wavelength light;
the detection unit (C) comprises a first photodiode (9) and a second photodiode (10), wherein the first photodiode (9) and the second photodiode (10) respectively perform photoelectric conversion on light with two different wavelengths and convert the light into two photocurrent signals;
the identification unit (D) comprises: the photoelectric conversion circuit comprises a first transimpedance amplifier (11), a second transimpedance amplifier (12) and a singlechip (13), wherein the first transimpedance amplifier (11) and the second transimpedance amplifier (12) respectively convert two photoelectric current signals into voltage signals and amplify the voltage signals to obtain two amplified voltage signals; the first transimpedance amplifier (11) and the second transimpedance amplifier (12) respectively send two amplified voltage signals to the singlechip (13); the singlechip (13) converts the two amplified voltage signals into two digital signals, calculates the ratio between the two digital signals, and identifies the plastic type of the tested plastic sample (7) according to the ratio.
2. A plastic identification system based on a dual wavelength coherent light source of the near infrared type according to claim 1, characterized in that said non-periodically poled crystal (5) is placed in a temperature controlled oven (4).
3. A plastic identification system based on a near infrared dual wavelength coherent light source according to claim 1, characterized in that the two different wavelengths of the dual signal light generated by said light source unit (a) are 1662nm and 1716nm, respectively; the first wavelength light separated by the optical filter (8) is light with the wavelength of 1662nm, and the second wavelength light is light with the wavelength of 1716nm; the plastic categories include: PVC, PET, PS.
4. A plastic identification system based on a dual wavelength coherent light source of the near infrared according to claim 3, characterized in that the digital signal converted based on light with wavelength of 1662nm is a first digital signal, the digital signal converted based on light with wavelength of 1716nm is a second digital signal, the ratio between the first digital signal and the second digital signal is R, if 0.8> R >0.7, the plastic type of the tested plastic sample (7) is PET; if 1> R >0.9, the plastic type of the tested plastic sample (7) is PS; if R >1.5, the plastic type of the tested plastic sample (7) is PVC.
5. A plastic identification system based on a near infrared dual wavelength coherent light source according to claim 1, characterized in that the transmittance of the input coupling mirror (3) to the band of pump light is higher than 95%; the reflectivity of the input coupling mirror (3) to two wave bands of the double-signal light is higher than 99%; the transmittance of the output coupling mirror (6) to two wave bands of the double-signal light is higher than 87%, and the reflectance to the wave band of the pump light is higher than 86%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111648368.5A CN114354531B (en) | 2021-12-30 | 2021-12-30 | Plastic identification system of dual-wavelength coherent light source based on near infrared |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111648368.5A CN114354531B (en) | 2021-12-30 | 2021-12-30 | Plastic identification system of dual-wavelength coherent light source based on near infrared |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114354531A CN114354531A (en) | 2022-04-15 |
| CN114354531B true CN114354531B (en) | 2024-02-02 |
Family
ID=81102895
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111648368.5A Active CN114354531B (en) | 2021-12-30 | 2021-12-30 | Plastic identification system of dual-wavelength coherent light source based on near infrared |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114354531B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115615953B (en) * | 2022-10-10 | 2024-04-19 | 合肥工业大学 | Differential absorption laser radar light source for detecting harmful gas in atmosphere environment |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106018324A (en) * | 2016-08-15 | 2016-10-12 | 中国计量大学 | Plastic identification apparatus and method based on near-infrared spectroscopy analysis |
| CN110487221A (en) * | 2019-08-20 | 2019-11-22 | 大连海事大学 | Hologram fringe central bright spot area and the micro- plastics detection device of dimension ratio and method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114185223B (en) * | 2020-09-15 | 2024-03-26 | 山东大学 | Parametric light generation method and application |
-
2021
- 2021-12-30 CN CN202111648368.5A patent/CN114354531B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106018324A (en) * | 2016-08-15 | 2016-10-12 | 中国计量大学 | Plastic identification apparatus and method based on near-infrared spectroscopy analysis |
| CN110487221A (en) * | 2019-08-20 | 2019-11-22 | 大连海事大学 | Hologram fringe central bright spot area and the micro- plastics detection device of dimension ratio and method |
Non-Patent Citations (1)
| Title |
|---|
| 1064nm泵浦温度调谐PPLN光学参量振荡器;徐龙浩;刁述妍;姚建铨;郑义;刘强;杨剑;;激光与红外(08);全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114354531A (en) | 2022-04-15 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101604055B (en) | Parallel double-chamber tunable fiber Fabry-Perot filter | |
| CN114354531B (en) | Plastic identification system of dual-wavelength coherent light source based on near infrared | |
| CN102243167A (en) | Terahertz wave imaging device | |
| CN108462469B (en) | Solar cell loss parameter measurement and analysis system and use method | |
| CN105651703A (en) | Method for measuring extinction coefficient of ring-down gas of optical cavity based on change of cavity length | |
| CA2376132A1 (en) | Method and apparatus for detecting mastitis by using visible light and/or near infrared light | |
| CN104535529A (en) | Distributed gas sensing system and control method thereof | |
| CN116046721B (en) | Correlation open-circuit laser gas detector and gas detection real-time calibration method | |
| CN116256338A (en) | Gas detection device and multi-component gas filtering inversion method thereof | |
| CN110411960A (en) | A kind of cavity ring-down spectroscopy instrument system | |
| CN110579447A (en) | Crop nitrogen detection device and detection method thereof | |
| CN110702607A (en) | High-cost-performance wide-spectrum photoacoustic spectrum gas detection device | |
| CN103884683B (en) | Based on the optical sensor of F-P semiconductor laser and the cascade of film F-P optical filter | |
| CN107478604B (en) | Device and method for measuring refractive index of transparent material | |
| CN116930121A (en) | Fiber bragg grating demodulation method and device based on VCSEL and acetylene absorption peak | |
| CN107860749A (en) | Based on CO2The portable SF of laser6Leak remote sensing instrument | |
| CN112595416A (en) | Broadband infrared spectrometer | |
| Jördens et al. | Fibre-coupled terahertz transceiver head | |
| US20100124790A1 (en) | Portable optical biosensor measuring apparatus and measurement method thereof | |
| CN106404695B (en) | Spectrophotometer | |
| CN114428057B (en) | Device and method for measuring wide-spectrum absorption characteristics of material | |
| CN210862726U (en) | Multichannel high-speed fiber grating demodulation module | |
| CN105259138A (en) | Z-scanning device for middle-infrared band being 3-5 micrometers | |
| CN211668647U (en) | Terahertz radiation detection device | |
| CN204165650U (en) | The Optical transmission spectrum measurement mechanism of ultra-narrow band pass filter |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |