A miniaturized near-infrared spectrometer imaging system

Abstract

The application relates to a miniaturized near-infrared spectrometer imaging system, and relates to the field of near-infrared spectrometers, which comprises a light source module, a sample light line generation module, a fiber coupler, a fiber F-P filter, a photodetector and a multimode optical fiber; the light generated by the light source module can irradiate a sample through the sample light line generation module and generate sample light lines; the fiber coupler and the fiber F-P filter are connected through the multimode optical fiber, and the fiber F-P filter and the photodetector are connected through the multimode optical fiber; the fiber coupler receives the sample light fiber and transmits the sample light fiber to the photodetector through the multimode optical fiber, the fiber F-P filter and the multimode optical fiber. The application has the effects of reducing the baseline drift and noise of the spectrum, improving the accuracy of the spectrum, and being smaller in size and lighter in weight.

Description

Technical Field

[0001] This application relates to the field of near-infrared spectrometers, and in particular to a miniaturized near-infrared spectrometer imaging system. Background Technology

[0002] Near-infrared spectrometers are instruments that use near-infrared spectroscopy to obtain information about samples. Due to their simple instrumentation, fast analysis speed, non-destructive nature, small sample preparation volume, suitability for analysis of almost all types of samples (liquids, viscous substances, coatings, powders, and solids), and simultaneous determination of multiple components and multiple channels, they are widely used in many fields, including agriculture, animal husbandry, food, chemical industry, petrochemical industry, pharmaceutical industry, and tobacco industry.

[0003] In existing near-infrared spectrometers, light reflected or transmitted from the sample passes through a grating and illuminates a photodetector. The photodetector converts the optical signal into an electrical signal, thus outputting the spectrum. However, in existing technologies, the light travels through space to the grating and then through space to the photodetector. During this spatial transmission, the refractive index of the air fluctuates due to temperature changes, leading to an increase in stray light. This causes baseline drift and noise superposition in the spectrum, resulting in reduced spectral accuracy. Summary of the Invention

[0004] To address the issue of increased stray light during the light dispersion process, which leads to baseline drift and noise superposition in the spectrum, resulting in reduced spectral accuracy, this application provides a miniaturized near-infrared spectrometer imaging system.

[0005] The miniaturized near-infrared spectrometer imaging system provided in this application adopts the following technical solution:

[0006] A miniaturized near-infrared spectrometer imaging system includes a light source module, a sample light generation module, an optical fiber coupler, an optical fiber FP filter, a photodetector, and a multimode optical fiber;

[0007] The light generated by the light source module can illuminate the sample through the sample light generation module and generate sample light. The fiber coupler and the fiber FP filter, as well as the fiber FP filter and the photodetector, are connected through the multimode fiber. The fiber coupler receives the sample light and transmits it to the photodetector through the multimode fiber, the fiber FP filter, and the multimode fiber.

[0008] By adopting the above technical solution, during sample detection, the light source module transmits the light source to the sample light generation module, generating sample light. This sample light is then transmitted to the input of the fiber optic coupler. After coupling by the fiber optic coupler, it is transmitted through a multimode fiber to a fiber optic FP filter. The specific wavelength light filtered by the fiber optic FP filter is then transmitted through another multimode fiber to the detector, completing the reception of the optical signal. The process of transmitting the sample light through the fiber optic coupler, multimode fiber FP filter, and multimode fiber to the photodetector ensures that the optical signal is transmitted within the multimode fiber, avoiding stray light contamination caused by air scattering and dust contamination, reducing spectral baseline drift and noise, and improving spectral accuracy. By combining the fiber optic FP filter with flexible multimode fiber, it can be flexibly arranged inside the instrument without requiring space for mechanical rotation. Compared to the original grating solution, this results in a smaller and lighter spectrometer.

[0009] Preferably, a condenser lens and a collimating lens are provided between the light source module and the sample light generation module, and the light generated by the light source module is transmitted to the sample light generation module after passing through the condenser lens and the collimating lens in sequence.

[0010] By adopting the above technical solution, the condenser lens and collimating lens focus and collimate the light generated by the light source module, so that the light is transmitted to the sample light generation module in a more concentrated and consistent direction, which enhances the utilization rate of light and helps to improve the intensity and quality of sample light, thereby improving the accuracy and sensitivity of spectral detection.

[0011] Preferably, the sample light generation module includes a semi-transparent and semi-reflective mirror and a sample carrier module. The sample carrier module is used to place the sample, and the semi-transparent and semi-reflective mirror can transmit incident light and reflect sample light to the fiber coupler.

[0012] By employing the above technical solution, a semi-transparent, semi-reflective mirror allows incident light to pass through and illuminate the sample, while simultaneously reflecting the sample light to the fiber optic coupler, enabling the detection of samples with high reflectivity. Through the transmission and reflection of light using the semi-transparent, semi-reflective mirror, the transmission path of light within the system is optimized, improving the utilization rate of the optical signal, thereby enhancing the efficiency and accuracy of the spectrometer in sample detection.

[0013] Preferably, the sample light generation module includes a transparent platform, through which incident light can pass and be transmitted from the sample to the fiber optic coupler.

[0014] By adopting the above technical solution, incident light can be transmitted through the sample to the fiber optic coupler using a transparent platform, which enables the detection of samples with low reflectivity and broadens the range of samples that the system can detect.

[0015] Preferably, a first reflector is provided between the collimating lens and the semi-transparent semi-reflective mirror. The first reflector can slide onto or deviate from the optical path of the incident light. The first reflector transmits the incident light to the sample through the incident lens group, and the sample light generated by the transmission of the sample is transmitted to the fiber coupler through the exit lens group.

[0016] By adopting the above technical solution, the first reflector can be flexibly slid onto or off the incident light path to change the light transmission path, so that the system can flexibly adjust the light path according to different detection requirements. This allows the optical fiber generated by the light source module to detect both low and high reflectivity samples, reducing the investment in the light source module and improving the economy of the spectrometer.

[0017] Preferably, the incident lens group includes a second reflector and a third reflector. The first reflector is at an angle of 45° to the incident light. The second reflector is arranged parallel to the first reflector. The third reflector is arranged perpendicular to the second reflector and is positioned opposite to the sample.

[0018] By adopting the above technical solution, a rectangular optical path composed of a first mirror, a second mirror, and a third mirror can be formed, which can effectively guide and deflect the incident light, so that the light can accurately illuminate the sample, optimize the light propagation path, improve the light utilization efficiency, and thus improve the quality of light generation in the sample.

[0019] Preferably, the exit mirror group includes a fourth reflector and a fifth reflector. The fourth reflector is arranged parallel to the second reflector and is used to reflect the sample light transmitted through the sample to the fifth reflector. The fifth reflector can reflect the sample light to the fiber coupler.

[0020] By adopting the above technical solution, the sample light transmitted through the sample is reflected by the fourth and fifth reflectors, and the sample light is successfully guided to the fiber optic coupler. This optimizes the transmission path of the sample light and ensures that the optical signal can be transmitted to the subsequent modules more efficiently and accurately.

[0021] Preferably, the fifth reflector is disposed in the optical path between the fiber coupler and the sample, and the fifth reflector can slide onto or off the optical path.

[0022] By adopting the above technical solution, the fifth reflector can slide onto or off the optical path as needed, flexibly controlling whether the sample light is transmitted to the fiber optic coupler. This enhances the system's control over light transmission, enabling the system to operate more efficiently under different detection requirements. Compared to a transmission mirror, the reflection of light by the reflector reduces light loss during transmission and increases the light intensity received by the photodetector.

[0023] Preferably, it also includes a linear drive mechanism, which is connected to the first reflector and the fifth reflector to drive the first reflector and the fifth reflector to slide onto or off the corresponding optical path.

[0024] By adopting the above technical solution, the linear drive mechanism drives the first and fifth reflectors to slide onto or off the corresponding optical paths, which can flexibly control the transmission path of light, facilitate switching for different detection needs, and improve the applicability and flexibility of the system.

[0025] Preferably, the fiber FP filter is a tunable fiber FP filter with an operating wavelength range of 780-2500nm.

[0026] By adopting the above technical solution, the tunable fiber FP filter can flexibly filter specific wavelengths of light in the 780-2500nm operating wavelength range to meet different detection needs and improve the applicability and flexibility of the system for detecting different samples.

[0027] In summary, this application includes at least one of the following beneficial technical effects:

[0028] 1. Optical signals are transmitted within multimode optical fibers, avoiding stray light from being mixed in due to air scattering and dust contamination during light transmission in space, reducing spectral baseline drift and noise, and improving spectral accuracy;

[0029] 2. Fiber FP filters paired with multimode fiber can be flexibly arranged inside the instrument without reserving space for mechanical rotation, thus reducing the size and weight of the spectrometer.

[0030] 3. By controlling the movement of the first and fifth reflectors, the spectrometer can detect both samples with high reflectivity and samples with low reflectivity, thereby broadening the range of samples that the system can detect. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of a miniaturized near-infrared spectrometer imaging system according to Embodiment 1 of this application.

[0032] Figure 2 This is a schematic diagram of a miniaturized near-infrared spectrometer imaging system according to Embodiment 2 of this application.

[0033] Figure 3 This is a schematic diagram of a miniaturized near-infrared spectrometer imaging system according to Embodiment 3 of this application.

[0034] Figure 4 This is a schematic diagram of a near-infrared spectrometer imaging system used to demonstrate the detection of samples with low refractive index.

[0035] Explanation of reference numerals in the attached figures: 11. Light source module; 12. Condenser lens; 13. Collimating lens; 14. Sample light generation module; 141. Semi-transparent and semi-reflective mirror; 142. Object carrier module; 143. Transparent object carrier platform; 15. Fiber optic coupler; 16. Fiber optic FP filter; 17. Photodetector; 18. Multimode fiber; 21. First reflector; 22. Incident mirror group; 221. Second reflector; 222. Third reflector; 23. Exit mirror group; 231. Fourth reflector; 232. Fifth reflector; 24. Linear drive mechanism. Detailed Implementation

[0036] The following will be combined with the appendix Figures 1-4 The technical solutions in the embodiments of the present invention are further described in detail below. The described embodiments are only possible technical implementations of the present invention, but are not limited thereto. Those skilled in the art can certainly combine the embodiments of the present invention to obtain other embodiments without creative effort, which are also within the protection scope of the present invention.

[0037] This application mainly uses optical fiber to transmit optical signals, combined with an adjustable filter, to reduce spectral baseline drift and noise, improve spectral accuracy, and reduce the size of the instrument. The following is a further detailed description of this application. Example 1

[0038] Reference Figure 1 A miniaturized near-infrared spectrometer imaging system includes a light source module 11, a condenser lens 12, a collimating lens 13, a sample light generation module 14, an optical fiber coupler 15, an optical fiber FP filter 16, a photodetector 17, and a multimode optical fiber 18. The spectrometer imaging system in this embodiment is suitable for samples with a reflectivity ≥5%.

[0039] In this embodiment, the light source module 11 is a high-stability halogen tungsten lamp as a near-infrared light source, with a wavelength coverage range of 750-2500nm, which can meet the needs of near-infrared spectral analysis.

[0040] The sample light generation module 14 includes a semi-transparent mirror 141 and a sample carrier module 142. The semi-transparent mirror 141 is a broadband multilayer dielectric film semi-transparent mirror with a uniform beam splitting ratio in the near-infrared region (780-2500nm). Its transmittance and reflectance can both reach between 45% and 55%, ensuring that the light emitted by the near-infrared light source can effectively pass through and illuminate the sample. At the same time, the light reflected from the sample can be efficiently reflected to the fiber coupler 15. The sample carrier module 142 is a transparent glass plate. The sample is placed on the sample carrier module 142. The incident light passing through the semi-transparent mirror 141 illuminates the sample to generate sample light, which is reflected back to the semi-transparent mirror 141 along the incident light path.

[0041] Fiber optic coupler 15 is a multimode fiber coupler. Its input port is aligned with the reflected light output direction of the semi-transparent mirror 141, and its output port is connected to the multimode fiber 18. The numerical aperture (NA) of fiber optic coupler 15 is 0.22, matching commonly used near-infrared transmission fibers, enabling efficient optical coupling and reducing optical loss. Its operating wavelength range covers 780-2500 nm, exhibiting low insertion loss (≤0.5 dB) throughout the entire near-infrared analysis band.

[0042] The multimode fiber 18 is a quartz multimode fiber with a core diameter of 600 μm, a cladding diameter of 660 μm, and a numerical aperture of 0.22, which is matched with the interface of the fiber coupler 15 and the fiber FP filter 16.

[0043] The fiber FP filter 16 is a tunable fiber FP filter with an operating wavelength range of 780-2500nm, perfectly matching the near-infrared analysis band. This filter achieves precise adjustment of the cavity length through piezoelectric ceramic actuation, thereby enabling the filtering of light at different wavelengths.

[0044] The photodetector 17 is an indium gallium arsenide (InGaAs) photodetector, which has high quantum efficiency in the near-infrared region (900-2500nm) (quantum efficiency ≥85% at 1550nm), and can efficiently convert the received optical signal into an electrical signal. The detector is equipped with a low-noise preamplifier, which can effectively reduce the impact of circuit noise on the detection results and improve the detection sensitivity.

[0045] In terms of optical path design, the light source module 11, condenser lens 12, collimating lens 13, semi-transparent and semi-reflective mirror 141, carrier module 142, fiber coupler 15, multimode fiber 18, fiber optic FP filter 16, and photodetector 17 are arranged in sequence according to the preset optical path order. The entire optical path system is encapsulated in a sealed metal shell, and the inner wall of the shell is treated with matte black finish to reduce stray light reflection and interference.

[0046] The light source module 11 generates incident light rays. After being focused by the condenser lens 12 and collimated by the collimating lens 13, the incident light rays form a parallel beam, making the incident light rays closer to the point light source. This allows the light rays to be transmitted to the sample light generation module 14 in a more concentrated and consistent direction, thereby enhancing the utilization rate of the light rays and helping to improve the intensity and quality of the sample light rays. The semi-transparent and semi-reflective mirror 141 is tilted at a 45° angle to the incident light path, so that the incident light can be incident on the semi-transparent and semi-reflective mirror 141 at a 45° angle. About 50% of the light passes through the semi-transparent and semi-reflective mirror 141 and is perpendicularly irradiated onto the sample surface on the sample carrier module 142. The sample light reflected from the sample surface is incident on the semi-transparent and semi-reflective mirror 141 again, and about 50% of the sample light is reflected to the input end of the fiber coupler 15. After being coupled by the fiber coupler 15, it is transmitted to the fiber FP filter 16 through the multimode fiber 18. The specific wavelength light filtered by the fiber FP filter 16 is then transmitted to the photodetector 17 through another section of multimode fiber 18 to complete the reception of the optical signal.

[0047] The implementation principle of Example 1 is as follows: During the spectral dispersion process, the sample light is transmitted to the photodetector 17 through the fiber coupler 15, the multimode fiber FP filter 16, and the multimode fiber 18. This allows the optical signal to be transmitted within the multimode fiber 18, avoiding stray light mixing caused by air scattering and dust contamination, reducing baseline drift and noise in the spectrum, and improving spectral accuracy. By combining the fiber FP filter 16 with the flexible multimode fiber 18, it can be flexibly arranged inside the instrument without reserving space for mechanical rotation. Compared with the original grating solution, this makes the spectrometer smaller and lighter. Example 2

[0048] Reference Figure 2 The difference between this embodiment and Embodiment 1 is that the sample light generation module 14 in this embodiment includes a transparent platform 143, which is also a transparent glass plate. The spectrometer imaging system in this embodiment is suitable for samples with reflectivity <5%. The incident light, after being collimated by the collimating lens 13, is perpendicularly irradiated onto the sample on the transparent platform 143. The output end of the fiber coupler 15 is positioned opposite to the sample light transmitted through the sample. After being coupled by the fiber coupler 15, the light is transmitted to the fiber FP filter 16 through the multimode fiber 18. The specific wavelength light filtered by the fiber FP filter 16 is then transmitted to the photodetector 17 through another section of multimode fiber 18 to complete the reception of the light signal and realize the detection of low reflectivity samples with reflectivity <5%. Example 3

[0049] See attached document Figure 3 , Figure 4The difference between this embodiment and Embodiment 1 is that a first reflector 21 is provided between the semi-transparent and semi-reflective mirror 141 and the collimating lens 13. The first reflector 21 is slidably connected to the outer shell and is inclined at a 45° angle to the incident light. The first reflector 21 transmits the incident light to the sample through the incident lens group 22. The sample light generated by transmitting the sample is transmitted to the fiber optic coupler 15 through the exit lens group 23. In this embodiment, the incident lens group 22 includes a second reflector 221 and a third reflector 222, and the exit lens group 23 includes a fourth reflector 231 and a fifth reflector 232. The second reflector 221 is arranged parallel to the first reflector 21, and the third reflector 222 is arranged perpendicular to the second reflector 221. The incident light is reflected by the first reflector 21 to the second reflector 221, and then reflected by the second reflector 221 to the third reflector 222, and then reflected by the third reflector 222 to the sample on the transparent platform 143.

[0050] The fourth reflector 231 and the third reflector 222 are set at a 180° interval along the circumference of the sample, and the fourth reflector 231 is set parallel to the second reflector 221, so that the sample light transmitted through the sample is transmitted to the fourth reflector 231. The fifth reflector 232 is set between the incident end of the fiber optic coupler 15 and the sample, and is located in the reflected light path between the sample and the fiber optic coupler 15. The fifth reflector 232 is slidably connected to the housing, and the sliding direction is the same as the sliding direction of the first reflector 21, so that the fifth reflector 232 can be separated from the reflected light path, thereby avoiding the transmission of light during the detection of samples with high reflectivity.

[0051] A linear drive mechanism 24 is fixedly provided on the outer casing. In this embodiment, the linear drive mechanism 24 is a lead screw and nut mechanism. The first reflector 21 and the fifth reflector 232 are both fixedly connected to the nut in the linear drive mechanism 24, so that the lead screw can move the first reflector 21 and the fifth reflector 232 at the same time.

[0052] The implementation principle of Example 3 is as follows: When it is necessary to detect a sample with high reflectivity (≥5%), the linear drive mechanism 24 drives the first reflector 21 to deviate from the optical path between the collimating lens 13 and the semi-transparent semi-reflective mirror 141, and the fifth reflector 232 to deviate from the incident optical path between the sample and the fiber optic coupler 15, so that the spectrometer imaging system can detect the sample with high reflectivity.

[0053] When it is necessary to detect samples with low reflectivity (<5%), the linear drive mechanism 24 drives the first reflector 21 to slide onto the optical path between the collimating lens 13 and the semi-transparent semi-reflective mirror 141, and the fifth reflector 232 to slide onto the incident optical path between the sample and the fiber optic coupler 15. This allows the incident light to illuminate the sample along the first reflector 21, the second reflector 221, and the third reflector 222. The sample light passing through the sample is transmitted along the fourth reflector 231 and the fifth reflector 232 to the incident end of the fiber optic coupler 15, enabling the spectrometer to detect samples with low reflectivity.

[0054] By moving the first reflector 21 and the fifth reflector 232, the incident light illuminates the sample along different optical paths, enabling the detection of both high-reflectivity and low-reflectivity samples, thereby expanding the spectrometer's applicability. Simultaneously, it reduces the investment in the light source module 11, improving the spectrometer's economic efficiency. Compared to a transmission mirror, the reflection of light by the reflector reduces light loss during transmission, increasing the light intensity received by the photodetector 17.

[0055] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A miniaturized near-infrared spectrometer imaging system, characterized in that: It includes a light source module (11), a sample light generation module (14), an optical fiber coupler (15), an optical fiber FP filter (16), a photodetector (17), and a multimode optical fiber (18); The light generated by the light source module (11) can illuminate the sample through the sample light generation module (14) and generate sample light. The fiber coupler (15) and the fiber FP filter (16), and the fiber FP filter (16) and the photodetector (17) are all connected through the multimode fiber (18). The fiber coupler (15) receives the sample light and transmits it to the photodetector (17) through the multimode fiber (18), the fiber FP filter (16), and the multimode fiber (18).

2. The miniaturized near-infrared spectrometer imaging system according to claim 1, characterized in that: A condenser lens (12) and a collimating lens (13) are provided between the light source module (11) and the sample light generation module (14). The light generated by the light source module (11) is transmitted to the sample light generation module (14) after passing through the condenser lens (12) and the collimating lens (13) in sequence.

3. The miniaturized near-infrared spectrometer imaging system according to claim 2, characterized in that: The sample light generation module (14) includes a semi-transparent and semi-reflective mirror (141) and a sample carrier module (142). The sample carrier module (142) is used to place the sample. The semi-transparent and semi-reflective mirror (141) can transmit incident light and reflect sample light to the fiber optic coupler (15).

4. The miniaturized near-infrared spectrometer imaging system according to claim 1, characterized in that: The sample light generation module (14) includes a transparent platform (143), through which incident light can pass and be transmitted from the sample to the fiber optic coupler (15).

5. The miniaturized near-infrared spectrometer imaging system according to claim 3, characterized in that: A first reflector (21) is provided between the collimating lens (13) and the semi-transparent semi-reflective mirror (141). The first reflector (21) can slide onto or deviate from the optical path of the incident light. The first reflector (21) transmits the incident light to the sample through the incident lens group (22). The sample light generated by the transmission of the sample is transmitted to the fiber optic coupler (15) through the exit lens group (23).

6. The miniaturized near-infrared spectrometer imaging system according to claim 5, characterized in that: The incident lens group (22) includes a second reflector (221) and a third reflector (222). The first reflector (21) has an angle of 45° with the incident light. The second reflector (221) is arranged parallel to the first reflector (21). The third reflector (222) is arranged perpendicular to the second reflector (221) and is positioned opposite to the sample.

7. The miniaturized near-infrared spectrometer imaging system according to claim 6, characterized in that: The exit mirror group (23) includes a fourth reflector (231) and a fifth reflector (232). The fourth reflector (231) is arranged parallel to the second reflector (221) and is used to reflect the sample light transmitted through the sample to the fifth reflector (232). The fifth reflector (232) can reflect the sample light to the fiber coupler (15).

8. The miniaturized near-infrared spectrometer imaging system according to claim 7, characterized in that: The fifth reflector (232) is disposed in the optical path between the fiber coupler (15) and the sample, and the fifth reflector (232) can slide onto or deviate from the optical path.

9. The miniaturized near-infrared spectrometer imaging system according to claim 7, characterized in that: It also includes a linear drive mechanism (24), which is connected to the first reflector (21) and the fifth reflector (232) so as to drive the first reflector (21) and the fifth reflector (232) to slide onto or off the corresponding optical path.

10. The miniaturized near-infrared spectrometer imaging system according to claim 1, characterized in that: The fiber FP filter (16) is a tunable fiber FP filter with a working wavelength range of 780-2500nm.

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