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CN-122016683-A - Gas detection imaging spectrometer based on DMD and transmission type grating

CN122016683ACN 122016683 ACN122016683 ACN 122016683ACN-122016683-A

Abstract

The invention discloses a gas detection imaging spectrometer based on a DMD and a transmission type grating, which comprises a gas detection imaging spectrometer body, a base, an angle seat and a camera interface ring, wherein the gas detection imaging spectrometer body solves the problem of detection errors caused by unstable ambient light, provides a reliable basis for gas characteristic absorption signal extraction, maintains high spectral resolution of 2.83nm-2.88nm by combining a DMD virtual slit with the transmission type grating, solves the contradiction between the resolution of the traditional fixed slit and the signal-to-noise ratio by slit self-adaption adjustment, ensures that the gas concentration detection errors are less than or equal to +/-3 percent, matches the characteristic absorption spectral lines of key components of natural gas and coal gas, meets the requirements of on-site movement detection, and has strong capability of inhibiting secondary spectrum and stray light interference and high detection stability by the synergistic effect of a light filtering unit and a PGP coaxial structure and a light source filter design.

Inventors

  • JI JIANCHENG
  • SU YUANYUAN

Assignees

  • 上海延目光电技术有限公司

Dates

Publication Date
20260512
Application Date
20260310

Claims (7)

  1. 1. The gas detection imaging spectrometer based on the DMD and the transmission grating comprises a gas detection imaging spectrometer body (38), a base (2), an angle seat (3) and a camera interface ring (4), and is characterized in that the base (2), the angle seat (3) and the camera interface ring (4) are arranged on the gas detection imaging spectrometer body (29); A lens cone A (7) is arranged in the base (2), and a filter disc A (9), a lens A (11), a lens B (13), a lens C (15), a cemented lens A (17) and a lens D (19) are sequentially arranged in the lens cone A (7) from left to right; A lens a (29), a lens b (31), a lens c (33), a cemented lens a (35) and a lens d (37) are arranged in the corner seat (3) in sequence from right to left; The end head of one end of the gas detection imaging spectrometer body (38) is provided with a lens mounting plate (1), the lens mounting plate (1) is matched with the left end of the base (2), the outer wall of one side of the base (2) is provided with a cover plate (28), the end head of the other end of the gas detection imaging spectrometer body (38) is provided with a camera interface ring (4), and the camera interface ring (4) is matched with the end head of one end of the corner seat (3); The gas detection imaging spectrometer comprises a gas detection imaging spectrometer body (38), wherein a Digital Micromirror Device (DMD) (39) and an incidence optical module (41) are arranged at the left end of the gas detection imaging spectrometer body in a matched mode, and a halogen lamp light source assembly (40) is arranged under the incidence optical module (41) in a matched mode.
  2. 2. The gas detection imaging spectrometer based on the DMD and the transmission grating according to claim 1, wherein a lens barrel pressing ring (8) is arranged on one side of the filter sheet A (9), a space ring A (10) is matched between the filter sheet A (9) and the lens A (11), a space ring B (12) is matched between the lens A (11) and the lens B (13), a space ring C (14) is matched between the lens B (13) and the lens C (15), a Mylar A (16) is matched between the lens C (15) and the lens A (17), and a space ring D (18) is matched on one side of the lens A (17).
  3. 3. The gas detection imaging spectrometer based on the DMD and the transmission grating according to claim 1, wherein a space ring b (30) is matched and arranged between a lens a (29) and a lens b (31) in the corner seat (3), a space ring c (32) is matched and arranged between the lens b (31) and a lens c (33), a Mylar a (34) is matched and arranged between the lens c (33) and a cemented lens a (35), and a space ring d (36) is matched and arranged between the cemented lens a (35) and a lens d (37).
  4. 4. The gas detection imaging spectrometer based on the DMD and the transmission type grating according to claim 1, wherein a slit sheet mounting ring (5) and a slit sheet (6) are arranged inside the left end head of the angle seat (3), and a grating mounting ring (20), a grating pressing ring (21), a grating (22), a prism mounting ring (23) and a prism (24) are matched inside the right end head of the angle seat (3).
  5. 5. The gas detection imaging spectrometer based on DMD and transmission grating according to claim 1, wherein the incident optical module (41) comprises a converging lens and a dust-proof window, and the object side NA of the converging lens is 0.205.
  6. 6. The gas detection imaging spectrometer based on the DMD and the transmission grating according to claim 1, wherein a spectrum correction algorithm is built in a signal processing module inside the Digital Micromirror Device (DMD) (39) to compensate spectral line offset caused by temperature change (5-40 ℃), and concentration detection precision errors are less than or equal to +/-3%.
  7. 7. The gas detection imaging spectrometer based on the DMD and the transmission grating according to claim 1, wherein the halogen lamp light source assembly (40) comprises a halogen lamp, a quartz collimating lens, an ultraviolet cut-off filter, a diaphragm and a high-precision direct-current stabilized power supply, the power of the halogen lamp light source is 5-20W, a broad-spectrum light beam of 300-2500nm is emitted, a core covers a 400-1000nm target wave band, the focal length of the quartz collimating lens is 10-20mm, the cut-off wavelength of the ultraviolet cut-off filter is 400nm, ultraviolet stray light is removed, and the aperture of the diaphragm is 2-5mm. The halogen lamp light source assembly (40) is connected with the incident optical module through a three-dimensional adjusting frame, the distance between the lamp body and the converging lens is 5-10 cm, the assembly is provided with a heat dissipation structure, the surface temperature of the lamp body is controlled to be less than or equal to 80 ℃, and the beam coupling efficiency is controlled to be more than or equal to 85%. The assembly and debugging process for realizing the DMD and transmission grating-based gas detection imaging spectrometer according to claim 1 comprises the following steps: The halogen lamp, the quartz collimating lens, the ultraviolet cut-off filter and the diaphragm are sequentially installed, so that coaxiality errors of all components are less than or equal to 0.02mm, a stabilized voltage power supply and a cooling fan are connected, the output stability of a light source is tested, the fluctuation of light intensity is less than or equal to +/-2 percent/h, the light source component is in butt joint with an incident optical module through a three-dimensional adjusting frame, the positions are adjusted to enable the center of a light beam to be aligned with the axis of a converging lens, and the coupling efficiency is more than or equal to 85 percent; Assembling according to the sequence of an incident optical module, a DMD, a transmission type grating spectrum module and a detection module, ensuring that coaxiality errors of all components are less than or equal to 0.01mm, adjusting a PGP coaxial structure, enabling grating lines to be perpendicular to the inclination direction of a prism, and keeping a gap of 2mm after fixation; Driving a micro-mirror array through a controller, respectively setting three virtual slit widths of 20 mu m, 50 mu m and 100 mu m, and calibrating slit light transmission consistency by utilizing a halogen lamp light source, wherein the error is controlled within +/-5%; Adopting standard gas samples (methane 5%, carbon monoxide 1%, ethane 2% and propane 1%), exciting and collecting characteristic absorption spectra through a halogen lamp under a standard environment (25 ℃ and 1 atm), establishing a standard spectrum library, storing the standard spectrum library in a signal processing module, and optimizing by an algorithm to realize that the spectrum matching precision is more than or equal to 98%; the modules are fixed on an aluminum alloy shell, a dustproof and waterproof window is arranged, the size of the shell is controlled to be 60 multiplied by 200mm, the weight is less than or equal to 1.2kg, and the power module (supporting direct current 12V power supply) and the alarm module are connected to complete the system integration.

Description

Gas detection imaging spectrometer based on DMD and transmission type grating Technical Field The invention relates to the technical field of gas detection imaging spectrometers, in particular to a gas detection imaging spectrometer based on a DMD and a transmission grating. Background Natural gas (mainly comprising methane, ethane and propane) and coal gas (mainly comprising carbon monoxide and hydrogen) are used as common fuels, and leak detection is important for safe production and environmental protection. In the existing gas detection technology, although the gas chromatography is high in precision, the analysis time is long (up to 45 minutes), professional operation is needed, the on-site rapid detection requirement is difficult to meet, the traditional infrared spectrum detection can only indicate the existence of gas and cannot realize multicomponent quantitative analysis, the conventional imaging spectrometer adopts a fixed slit design, the contradiction that the resolution and the signal to noise ratio are difficult to consider exists, the screening pertinence of the characteristic spectral line of the gas is insufficient, the interference of ambient light is easy, and the detection sensitivity is limited. Meanwhile, the existing spectrum detection technology based on the DMD is mostly applied to ultraviolet or infrared wave bands, is not combined with the high-resolution light splitting advantage of a transmission grating, and lacks customized stable light source adaptation design, namely, the environment light intensity fluctuation is large, the spectrum coverage is incomplete, so that gas characteristic absorption signals are weak, the detection precision and the stability are insufficient, and the on-site rapid detection requirement of multicomponent gases such as natural gas, coal gas and the like is difficult to adapt, so that an improved technology is needed to solve the problem in the prior art. Disclosure of Invention The invention aims to overcome the defects of the existing gas detection technology, provides a gas detection imaging spectrometer based on a DMD and a transmission type grating, realizes 400-1000nm wave band stable light beam output through integrating a halogen light source component, completes rapid identification and quantitative detection of multicomponent gases such as natural gas, coal gas and the like by matching with a DMD virtual slit and a high-resolution light splitting design, and combines detection precision and field adaptability, so as to solve the problems in the background technology. The invention provides a gas detection imaging spectrometer based on a DMD and a transmission grating, which comprises a gas detection imaging spectrometer body, a base, an angle seat and a camera interface ring, wherein the base, the angle seat and the camera interface ring are arranged on the gas detection imaging spectrometer body; a lens cone A is arranged in the base, and a filter disc A, a lens B, a lens C, a cemented lens A and a lens D are sequentially arranged in the lens cone A from left to right; the inside of the corner seat is provided with a lens a, a lens b, a lens c, a cemented lens a and a lens d in sequence from right to left; The end head of one end of the gas detection imaging spectrometer body (38) is provided with a lens mounting plate, the lens mounting plate is matched with the left end of the base, the outer wall of one side of the base is provided with a cover plate, the end head of the other end of the gas detection imaging spectrometer body is provided with a camera interface ring, and the camera interface ring is matched with the end head of one end of the corner seat; the gas detection imaging spectrometer comprises a gas detection imaging spectrometer body, wherein a Digital Micromirror Device (DMD) and an incident optical module are arranged at the end of the left end of the gas detection imaging spectrometer body in a matched mode, and a halogen lamp light source component is arranged under the incident optical module in a matched mode. Preferably, a lens barrel pressing ring is arranged on one side of the filter sheet A, a space ring A is matched between the filter sheet A and the lens A, a space ring B is matched between the lens A and the lens B, a space ring C is matched between the lens B and the lens C, a Mylar A is matched between the lens C and the lens A, and a space ring D is matched on one side of the lens A. Preferably, a spacer ring b is arranged between the lens a and the lens b in the corner seat in a matched mode, a spacer ring c is arranged between the lens b and the lens c in a matched mode, a Mylar sheet a is arranged between the lens c and the cemented lens a in a matched mode, and a spacer ring d is arranged between the cemented lens a and the lens d in a matched mode. Preferably, the left end of the corner seat is internally provided with a crack piece mounting ring and a crack piece, and the right end of the corner seat