A detection device and detection method for sunlight-induced excitation spectrum

Abstract

A detection device and method for sunlight-induced excitation spectrum. The detection device includes a Fresnel lens, a focusing lens, a chopper, a photoelectric sensor, a collection mirror, an optical fiber, a spectrometer, and a computer. The focusing lens is located below the Fresnel lens, a chopper is located behind the focusing lens, and the photoelectric sensor is located on the chopper. The collection mirror and the photoelectric sensor are spaced apart. The collection mirror is connected to one end of the optical fiber, and the other end of the optical fiber is connected to the spectrometer. The spectrometer is connected to the computer. The present invention uses sunlight as an excitation source to achieve plasma excitation of the object to be tested, and utilizes plasma spectroscopy to analyze the type and elemental composition of the object to be tested. This facilitates the realization of a low-cost and low-energy component detection device, and is convenient for field testing. In addition, the present invention also provides a detection method for the detection device.

Description

Technical Field

[0001] The present invention relates to the technical field of emission spectrum detection, and in particular to a detection device and method for sunlight-induced excitation spectrum. Background Art

[0002] Spectroscopic detection technology, which uses the spectrum of a substance to identify it or determine its chemical composition, has become an essential detection method in our lives and lives. Spectroscopic analysis techniques using lasers as the spectral excitation source have been widely studied and applied due to their rapidity, non-contact nature, high sensitivity, and simple sample preparation.

[0003] Laser-induced breakdown spectroscopy is a plasma emission spectroscopy analysis technology using laser as the excitation source. It has the advantages of being fast, remote, sample-free, real-time, and capable of in-situ detection. However, the high-energy pulsed laser it uses is expensive, consumes a lot of energy, and is inconvenient to use in the field. Summary of the Invention

[0004] Based on this, in order to overcome the shortcomings of the existing laser spectroscopy technology that uses lasers with high price and high energy consumption, the present invention provides a detection device and detection method for sunlight-induced excitation spectrum, aiming to solve the problems of high cost and high energy consumption of laser spectroscopy equipment, and to provide a low-cost and low-energy spectral detection device and detection method.

[0005] In a first aspect, the present invention provides a detection device for sunlight-induced excitation spectrum, comprising a Fresnel lens, a focusing lens, a chopper, a photoelectric sensor, a collecting mirror, an optical fiber, a spectrometer, and a computer. The focusing lens is provided below the Fresnel lens, a chopper is provided behind the focusing lens, the photoelectric sensor is provided on the chopper, the collecting mirror and the photoelectric sensor are spaced apart, one end of the optical fiber is connected to the rear of the collecting mirror, the other end of the optical fiber is connected to the spectrometer, and the spectrometer is connected to the computer.

[0006] Furthermore, the Fresnel lens and the focusing lens are coaxially placed, and the focusing lens is placed on the focal plane of the Fresnel lens.

[0007] Furthermore, the chopper is disc-shaped and has a plurality of circular holes distributed in a ring shape.

[0008] Furthermore, the photoelectric sensor is connected to the spectrometer, and the photoelectric sensor is used to detect the on-off of the chopper to sunlight and generate a trigger signal, and the trigger signal is used to control the operation of the spectrometer.

[0009] Furthermore, the sunlight is converged by the Fresnel lens and then irradiated on the focusing lens. The sunlight is further converged by the focusing lens and then passes through the circular hole of the chopper. The converged sunlight is focused on the surface of the inspection object.

[0010] Furthermore, the focus of one end of the collecting mirror is aligned with the ablation point of the sunlight on the surface of the inspection object, and the focus of the other end of the collecting mirror is aligned with the end face of the optical fiber.

[0011] In a second aspect, the present invention further provides a detection method using the detection device described in any one of the above items, wherein sunlight is irradiated on a Fresnel lens, converged by the Fresnel lens, then passes through a focusing lens, and then through a circular hole in a chopper. The converged sunlight is focused on the surface of the object being tested, and the high temperature generated in the focused area of ​​the sunlight causes the surface of the object to be ablated, thereby exciting and forming plasma.

[0012] During the rotation of the chopper, sunlight is cut off or conducted. A photoelectric sensor is installed on the chopper. The photoelectric sensor uses the reflection and transmission of light during the chopper's rotation to detect the chopper's rotation cycle and generate a trigger signal. This signal triggers the spectrometer. When light passes through the chopper and is focused on the surface of the object to be measured, the spectrometer starts collecting data.

[0013] The collecting mirror is aimed at the plasma in the ablation area of ​​the surface of the object to be tested caused by sunlight. The plasma light enters the collecting mirror and is transmitted to the spectrometer via the optical fiber connected to the collecting mirror. The spectrometer splits the plasma light to form a spectrum, and the spectral signal is transmitted to the computer. The computer uses the collected spectral signal to analyze the types and contents of elements contained in the object to be tested.

[0014] The detection device and method of solar-induced excitation spectroscopy of the present invention differ from the existing technology in that: solar-induced excitation spectroscopy technology uses sunlight as a spectral excitation source, which can achieve energy-free spectral excitation, and uses plasma spectroscopy to perform component analysis on the object to be tested. It is also a low-cost spectral analysis technology that can realize spectral detection in the field and deep space environments. It has a fast analysis speed, does not require sample preparation, and can realize in-situ and contactless analysis of samples.

[0015] The present invention is beneficial for spectrum detection in the wild and deep space environments, and has the following technical features:

[0016] (1) A large-aperture Fresnel lens is used to collect sunlight, and then a converging lens is used to focus the sunlight on the surface of the sample to be tested. The high energy density of the sunlight generates a high temperature that excites the sample to be tested to produce plasma. Therefore, the present invention can achieve zero power consumption and low-cost plasma spectrum excitation;

[0017] (2) Using a chopper and a photoelectric sensor to generate a spectrometer trigger signal, the trigger signal is used to control the spectrum acquisition time of the spectrometer and photoelectric detector to achieve synchronization between plasma excitation and spectrum detection;

[0018] (3) No sample preparation is required and it is not restricted by the morphology of the object being tested. It can achieve rapid identification of material types and analysis of element content in the field or deep space environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a system principle diagram of Example 1 of the present invention;

[0020] Figure 2 This is a system principle diagram of embodiment 2 of the present invention;

[0021] Figure 3 The spectra collected by the present invention for 14 rock samples;

[0022] Figure 4 This is a classification model diagram of 14 rock samples established by the present invention in combination with the principal component analysis method;

[0023] In the figure: 1 - sunlight, 2 - Fresnel lens, 21 - large-aperture concave mirror with hole, 22 - concave mirror, 3 - focusing lens, 4 - chopper, 5 - photoelectric sensor, 6 - plasma, 7 - detection object, 8 - collection mirror, 9 - optical fiber, 10 - spectrometer, 11 - computer. DETAILED DESCRIPTION

[0024] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the accompanying drawings. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present disclosure.

[0025] Example 1

[0026] See also Figure 1-Figure 2 The present invention provides a detection device for sunlight-induced excitation spectrum, comprising a Fresnel lens 2, a focusing lens 3, a chopper 4, a photoelectric sensor 5, a collection mirror 8, an optical fiber 9, a spectrometer 10, and a computer 11. The focusing lens 3 is provided below the Fresnel lens 2, the chopper 4 is provided below the focusing lens 3, the photoelectric sensor 5 is mounted on the chopper 4, the collection mirror 8 focuses on the plasma 6 generated by ablation of the focusing lens 3 on the surface of the detection object 7, the other end of the collection mirror 8 focuses on the incident section of the optical fiber 9, the other end of the optical fiber 9 is connected to the spectrometer 10, and the spectrometer 10 is connected to the computer 11.

[0027] The Fresnel lens 2 and the focusing lens 3 are coaxially arranged, and the focusing lens 3 is placed at the focal plane of the Fresnel lens 2. The chopper is in the shape of a disk, and has a plurality of circular holes distributed in an annular pattern.

[0028] The photoelectric sensor is connected to the spectrometer. The photoelectric sensor 5 is used to detect the on / off of the sunlight by the chopper 4 and generate a trigger signal. The photoelectric sensor 5 is connected to the spectrometer 10. The trigger signal generated by the photoelectric sensor 5 controls the spectrometer 10.

[0029] The sunlight is converged by the Fresnel lens and irradiated on the focusing lens, and is further converged by the focusing lens. Finally, the sunlight passes through the circular hole of the chopper and is focused on the surface of the inspection object.

[0030] The focus of one end of the collecting mirror is aligned with the ablation point of the sunlight on the surface of the detection object, and the focus of the other end of the collecting mirror is aligned with the end face of the optical fiber.

[0031] In this embodiment, the Fresnel lens has a diameter of 500 mm and a focal length of 500 mm; the focusing lens has a diameter of 50 mm and a focal length of 150 mm; the chopper has four circular holes with a diameter of 30 mm, with the hole centers evenly distributed in a ring 50 mm from the center of the chopper; the spectrometer is an AvaSpec-ULS2048 model from Avantes, the Netherlands, with a wavelength range of 200-1100 nm and a maximum resolution of 0.05 nm; the detector of the spectrometer is a 2048-pixel CCD array with an integration time of 1.1 ms; and the test objects are 14 rock samples, including galena, cinnabar, talc, molybdenite, pyrite, hematite, magnetite, chalcopyrite, fluorite, quartz, graphite, sphalerite, stibnite, and tungsten ore.

[0032] The specific working process is:

[0033] Sunlight 1 strikes a Fresnel lens 2, where it is focused and then passes through a focusing lens 3 before passing through a circular aperture in a chopper 4. The focused sunlight is then focused onto the surface of an object 7 under test. The high temperature generated in the focused region of the sunlight 1 causes ablation and excitation of the object's surface, forming a plasma 6. The chopper 4 has a circular aperture. As it rotates, it interrupts or conducts the focused sunlight 1. A photoelectric sensor 5 is mounted on the chopper 4. This sensor detects the rotation cycle of the chopper 4 by reflecting and transmitting the sunlight 1 during its rotation, generating a trigger signal. This signal generates a high level when light is transmitted and a low level when light is not transmitted. This trigger signal controls the operating state of a spectrometer 10. When light passes through the chopper 4 and is focused on the surface of the object 7 under test, the high trigger signal triggers the spectrometer 10 to begin collecting data. The collecting mirror 8 is aimed at the plasma 6 generated by the sunlight 1 on the ablation area of ​​the surface of the object to be tested 7. The light from the plasma 6 enters the collecting mirror 8 and is transmitted to the spectrometer 10 via the optical fiber 9 connected to the collecting mirror 8. The spectrometer 10 splits the collected light from the plasma 6 to form a spectrum. The spectral signal is converted into electrical signal spectrum data by the photoelectric detector, and the electrical signal spectrum data is transmitted to the computer 11. The computer 11 uses the collected spectral data to analyze the elements contained in the object to be tested 7, determines the type of element by the wavelength of the element characteristic spectrum line, and determines the content of the element by the intensity of the element characteristic spectrum line. Due to the large fluctuation of sunlight intensity, the obtained spectrum needs to be background subtracted and normalized before spectral analysis. The spectra obtained from the detection of 14 types of rocks are as follows: Figure 3 As shown in the figure, the classification and recognition model of 14 rock samples was established using the above spectral data and principal component analysis method. Figure 4 shown.

[0034] Example 2

[0035] See also Figure 1-Figure 2 The present invention provides a detection device for sunlight-induced excitation spectrum, comprising a large-aperture concave mirror 21 with a hole, a concave mirror 22, a focusing lens 3, a chopper 4, a photoelectric sensor 5, a collection mirror 8, an optical fiber 9, a spectrometer 10 and a computer 11. The focusing lens 3 is provided under the Fresnel lens 2, the chopper 4 is provided under the focusing lens 3, the photoelectric sensor 5 is mounted on the chopper 4, the collection mirror 8 focuses on the plasma 6 generated by ablation of the focusing lens 3 on the surface of the detection object 7, the other end of the collection mirror 8 focuses on the incident section of the optical fiber 9, the other end of the optical fiber 9 is connected to the spectrometer 10, and the spectrometer 10 is connected to the computer 11.

[0036] The large-aperture concave mirror 21, the concave mirror 22 and the focusing lens 3 are coaxially placed, the concave mirror 22 is at the focus of the large-aperture concave mirror 21, and the focusing lens 3 is placed below the large-aperture concave mirror 21. Figure 2As shown, other components and compositions are the same as those in Example 1.

[0037] The specific working process is:

[0038] The reflective surface of the large-aperture concave mirror 21 faces the incident direction of the sunlight 1. The large-aperture concave mirror 21 focuses the sunlight 1 onto the concave mirror 22. The reflective surface of the concave mirror 22 faces downward and is aligned with the center hole of the large-aperture concave mirror 21. The concave mirror 22 reflects the received sunlight and transmits it through the center hole of the large-aperture concave mirror to the focusing lens 3. The sunlight then passes through the circular hole in the chopper 4. After being concentrated by the focusing lens 3, it is focused on the surface of the object 7 to be measured. Under the influence of the high temperature generated in the focused area of ​​the sunlight, the surface of the object is ablated and excited to form plasma 6. The other operating methods and processes are the same as those in Example 1.

[0039] The present invention provides a detection device and method for solar-induced excitation spectroscopy, which differ from the prior art in that solar-induced excitation spectroscopy technology uses sunlight as a spectral excitation source, can achieve energy-free spectral excitation, and uses plasma spectroscopy to perform component analysis on the object to be tested. It is also a low-cost spectral analysis technology that can realize spectral detection in the field and deep space environments, has a fast analysis speed, does not require sample preparation, and can realize in-situ and contactless analysis of samples.

[0040] The present invention is beneficial for spectrum detection in the wild and deep space environments, and has the following technical features:

[0041] (1) A large-aperture Fresnel lens is used to collect sunlight, and then a converging lens is used to focus the sunlight on the surface of the sample to be tested. The high energy density of the sunlight generates a high temperature that excites the sample to be tested to produce plasma. Therefore, the present invention can achieve zero power consumption and low-cost plasma spectrum excitation;

[0042] (2) Using a chopper and a photoelectric sensor to generate a spectrometer trigger signal, the trigger signal is used to control the spectrum acquisition time of the spectrometer and photoelectric detector to achieve synchronization between plasma excitation and spectrum detection;

[0043] (3) No sample preparation is required and it is not restricted by the morphology of the object being tested. It can achieve rapid identification of material types and analysis of element content in the field or deep space environment.

[0044] The above embodiments merely illustrate the implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, and these modifications and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A detection device for sunlight-induced excitation spectrum, characterized in that: The invention adopts sunlight as a plasma excitation light source, and comprises a Fresnel lens, a focusing lens, a chopper, a photoelectric sensor, a collecting mirror, an optical fiber, a spectrometer and a computer. The focusing lens is arranged below the Fresnel lens, a chopper is arranged behind the focusing lens, the photoelectric sensor is arranged on the chopper, the collecting mirror and the photoelectric sensor are arranged at intervals, the photoelectric sensor is connected to the external trigger end of the spectrometer, the collecting mirror is connected to one end of the optical fiber, the other end of the optical fiber is connected to the spectrometer, and the spectrometer is connected to the computer; the Fresnel lens and the focusing lens are coaxially arranged, and the focusing lens is arranged at a position equal to or greater than 0.05mm. The chopper is in the focal plane of the Fresnel lens; the chopper is disc-shaped and has a plurality of circular holes distributed in an annular pattern; the photoelectric sensor is connected to the spectrometer, and is used to detect whether the chopper is on or off with respect to sunlight, and to generate a trigger signal, which is used to control the operation of the spectrometer; the sunlight is converged by the Fresnel lens and then irradiated onto the focusing lens, where it is further converged and then passes through the circular holes of the chopper, where the converged sunlight is focused on the surface of the inspection object; the focus of one end of the collection mirror is aligned with the ablation point of the sunlight on the surface of the inspection object, and the focus of the other end of the collection mirror is aligned with the end face of the optical fiber.

2. A detection method using the detection device as claimed in claim 1, characterized in that: Sunlight shines on the Fresnel lens, is focused by the Fresnel lens, passes through the focusing lens, and then passes through the circular hole on the chopper. The focused sunlight is focused on the surface of the object being measured. Under the action of the high temperature generated in the focused area of ​​the sunlight, the surface of the object is ablated and excited to form plasma. During the rotation of the chopper, sunlight is cut off or conducted. A photoelectric sensor is installed on the chopper. The photoelectric sensor uses the reflection and transmission of light during the chopper's rotation to detect the chopper's rotation cycle and generate a trigger signal. This signal triggers the spectrometer. When light passes through the chopper and is focused on the surface of the object to be measured, the spectrometer starts collecting data. The collecting mirror is aimed at the plasma in the ablation area of ​​the surface of the object to be tested caused by sunlight. The plasma light enters the collecting mirror and is transmitted to the spectrometer via the optical fiber connected to the collecting mirror. The spectrometer splits the plasma light to form a spectrum, and the spectral signal is transmitted to the computer. The computer uses the collected spectral signal to analyze the types and contents of elements contained in the object to be tested.

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