A method and device for effectively improving the detection accuracy of a spectrometer

Abstract

The present invention provides a method and device for effectively improving the detection accuracy of a spectrometer, comprising the following steps: keeping the laser horizontal; installing the infrared light source on an infrared light source mounting frame; installing the collimator on the collimator frame; making the horizontal plane where the focus of the collimator coincide with the horizontal plane where the infrared light source is located, and adjusting the lateral position of the infrared light source, fixing the lateral position of the infrared light source after the vertical plane where the focus is located coincides with the vertical plane where the infrared light source is located; adjusting the angle of the collimator so that the scattered light emitted by the laser forms a light spot on the intersection of the horizontal plane where the infrared light source is located and the vertical plane; adjusting the longitudinal position of the infrared light source, and fixing the longitudinal position of the infrared light source when the center of the infrared light source coincides with the focal position of the collimator. The method and device provided by the present invention can fundamentally solve the collimation problem of the infrared light source by collecting stray light and cooperating with the optical path arrangement and the adjustment mechanism.

Description

Technical Field

[0001] The present invention relates to the technical field of spectrometers, and in particular to a method and a device for effectively improving the detection accuracy of a spectrometer. Background Art

[0002] Ideally, the point light source of the spectrometer can radiate infinite energy outward with ideal collimation. But in reality, any light source has a certain luminous area, and to obtain more energy, it is necessary to use an extended light source with a larger surface size. The offset between the aperture size of the extended light source and its position will affect the interference signal and limit the resolution index of the instrument. The general means to eliminate this effect are:

[0003] 1. Calibrate the wavelength by comparing the spectrum of standard substances;

[0004] 2. Position the light source and collimator by improving processing accuracy;

[0005] These two methods have the following disadvantages:

[0006] 1. The calibration method cannot be completely calibrated, and there will still be some deviations, making the wavelength error of each instrument inconsistent.

[0007] 2. Calibration by improving processing accuracy increases processing difficulty and cost. Secondly, the error is not eliminated and the error between stages is still uncertain. Summary of the invention

[0008] The present invention aims to overcome one of the above-mentioned defects existing in the prior art, and provides a method and device for effectively improving the detection accuracy of a spectrometer, which can effectively solve the problem of inaccurate light source assembly, thereby improving the detection accuracy of the spectrometer.

[0009] A method for effectively improving the detection accuracy of a spectrometer comprises the following steps:

[0010] ——Install the laser of the laser incident module on the laser mounting frame and keep the laser level;

[0011] ——Install the infrared light source of the infrared light source module on the infrared light source mounting frame;

[0012] ——Install the collimator of the infrared light source module on the collimator frame;

[0013] -- Use an imaging plate to observe the position of the collimator's focus, so that the horizontal plane where the focus is located coincides with the horizontal plane where the infrared light source is located, and adjust the lateral position of the infrared light source so that the vertical plane where the focus is located coincides with the vertical plane where the infrared light source is located, and then fix the lateral position of the infrared light source;

[0014] ——Adjust the angle of the collimator so that the scattered light emitted by the laser is collected by the collimator and forms a light spot on the intersection of the horizontal plane and the vertical plane where the infrared light source is located. The location of the light spot is the exact location of the focus of the collimator;

[0015] ——Adjust the longitudinal position of the infrared light source. When the center of the infrared light source completely coincides with the exact position of the collimator focus, fix the longitudinal position of the infrared light source.

[0016] A device for effectively improving the detection accuracy of a spectrometer, the spectrometer comprising a base, an infrared light source module, and a laser incident module, the laser incident module comprising a laser bracket and a laser, the laser bracket being fixedly mounted on the base, the laser being mounted on the laser bracket, the infrared light source module comprising a collimator, a collimator seat, a light source bracket, a light source seat, and a light source, the collimator seat being fixedly mounted on the base, the collimator being rotatably mounted on the collimator seat, the light source bracket being mounted on the base and moving laterally along the base, the light source seat being fixedly mounted on the light source bracket, the light source being mounted on the light source seat, and moving longitudinally along the light source seat.

[0017] Optimally, a heat-insulating bracket is fixedly mounted on the base, a transverse long hole is opened on the light source bracket, and the light source bracket and the heat-insulating bracket are fixedly connected at the long hole by bolts.

[0018] Furthermore, a longitudinal light source mounting hole is opened in the middle of the light source seat, a vertical top screw mounting hole connected to the light source mounting hole is opened in the upper part of the light source seat, the light source passes through the longitudinal light source mounting hole, and a top screw is installed at the top screw mounting hole.

[0019] Optimized, the collimator seat is an L-shaped structure, including an integrally formed horizontal seat and a vertical seat, the horizontal seat is fixedly mounted on the base, the middle part of the collimator is rotatably mounted on the vertical seat via a rotating shaft, and the collimator is provided with a circle of screw countersunk holes on the periphery of the rotating shaft, the collimator and the vertical seat are connected at the screw countersunk holes by countersunk bolts, and the diameter of the countersunk bolts is smaller than the aperture of the screw countersunk holes.

[0020] Furthermore, there are two laser brackets, the top of the laser bracket is provided with an arc-shaped laser clearance, an elastic gasket is installed at the laser clearance position, an elastic pressing plate is provided above the laser, and both ends of the elastic pressing plate are fixedly connected to the laser bracket by bolts.

[0021] Furthermore, a device for effectively improving the detection accuracy of a spectrometer also includes an interferometer module and a convergence module fixedly mounted on a base.

[0022] Optimally, a light source cover is fixedly installed on the light source bracket, a light transmission hole is opened on the upper side of the light source cover, a top screw installation hole is opened on the top, and an aperture is fixedly installed in the light source cover.

[0023] Beneficial effects of the present invention:

[0024] Beneficial effects achieved by the present invention:

[0025] The present invention can fundamentally solve the problem of infrared light source collimation by collecting "useless" stray light through optical path arrangement and adjustment mechanism, so that the instrument can maintain good consistency in batch production and improve the detection accuracy of the spectrometer. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is one of the structural diagrams of the present invention;

[0027] Figure 2 This is the second structural diagram of the present invention;

[0028] Figure 3 It is a schematic diagram of the structure of the laser incident module;

[0029] Figure 4 This is a schematic diagram of the impact of the extended light source;

[0030] Figure 5 This is a schematic diagram of the extended light source offset;

[0031] Figure 6 Schematic diagram of defocusing of extended light source;

[0032] In the figure, 1. laser bracket, 2. laser, 3. base, 4. vertical seat, 5. interferometer module, 6. horizontal seat, 7. light source, 8. light source seat, 9. thermal insulation bracket, 10. light source cover, 11. collimator, 12. countersunk bolt, 13. rotating shaft, 14. convergence module, 15. top screw mounting hole, 16. light source bracket, 17. horizontal long hole, 18. elastic pressure piece, 19. elastic gasket, 20. laser makes way. DETAILED DESCRIPTION

[0033] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] A method for effectively improving the detection accuracy of a spectrometer comprises the following steps:

[0035] ——Install the laser of the laser incident module on the laser mounting frame and keep the laser level;

[0036] ——Install the infrared light source of the infrared light source module on the infrared light source mounting frame;

[0037] ——Install the collimator of the infrared light source module on the collimator frame;

[0038] -- Use an imaging plate to observe the position of the collimator's focus, so that the horizontal plane where the focus is located coincides with the horizontal plane where the infrared light source is located, and adjust the lateral position of the infrared light source so that the vertical plane where the focus is located coincides with the vertical plane where the infrared light source is located, and then fix the lateral position of the infrared light source;

[0039] ——Adjust the angle of the collimator so that the scattered light emitted by the laser is collected by the collimator and forms a light spot on the intersection of the horizontal plane and the vertical plane where the infrared light source is located. The location of the light spot is the exact location of the focus of the collimator;

[0040] ——Adjust the longitudinal position of the infrared light source. When the center of the infrared light source completely coincides with the exact position of the collimator focus, fix the longitudinal position of the infrared light source.

[0041] A device for effectively improving the detection accuracy of a spectrometer, the spectrometer comprises a base 3, an infrared light source module, and a laser incident module, the laser incident module comprises a laser bracket 1 and a laser 2, the laser bracket is fixedly mounted on the base, the two can be fixedly connected by bolts, or by other connection methods, and the laser is mounted on the laser bracket.

[0042] The infrared light source module includes a collimator 11, a collimator seat, a light source bracket 16, a light source seat 8 and a light source 7. The collimator seat is fixedly mounted on the base, and the two can be fixedly connected by bolts, or fixed by other connection methods. The collimator is rotatably mounted on the collimator seat, the light source bracket is mounted on the base and moves laterally along the base, the light source seat is fixedly mounted on the light source bracket, and the light source seat and the light source bracket can be fixedly connected by bolts, or can be integrally formed or fixed by other methods. The light source is mounted on the light source seat and moves longitudinally along the light source seat.

[0043] Optimally, a heat-insulating bracket 9 is fixedly installed on the base, and a transverse long hole 17 is opened on the light source bracket. The light source bracket and the heat-insulating bracket are fixedly connected at the long hole by bolts, so that the light source bracket can drive the light source to move laterally along the heat-insulating bracket, so that the center of the light source is laterally aligned with the focus of the collimator.

[0044] Furthermore, a longitudinal light source mounting hole is opened in the middle of the light source seat, and a vertical top screw mounting hole connected to the light source mounting hole is opened in the upper part of the light source seat. The light source passes through the longitudinal light source mounting hole, and a top screw is installed at the top screw mounting hole. The light source can move along the light source mounting hole of the light source seat so that the center of the light source is aligned with the focus of the collimating mirror in the longitudinal direction, thereby realizing the calibration of the light source position.

[0045] Optimized, the collimator seat is an L-shaped structure, including an integrally formed horizontal seat 6 and a vertical seat 4, the horizontal seat is fixedly mounted on the base, the middle part of the collimator is rotatably mounted on the vertical seat through a rotating shaft 13, and the collimator is provided with a circle of screw countersunk holes on the periphery of the rotating shaft, the collimator and the vertical seat are connected at the screw countersunk holes by countersunk bolts 12, and the diameter of the countersunk bolts is smaller than the aperture of the screw countersunk holes, the installation of the collimator is relatively stable, and the collimator can be rotated along the rotating shaft by a certain angle, so that the collimator can collect the stray light emitted by the laser.

[0046] Furthermore, there are two laser brackets, and an arc-shaped laser clearance 20 is opened on the top of the laser bracket. An elastic gasket 19 is installed at the laser clearance. An elastic pressing plate 18 is provided above the laser. The two ends of the elastic pressing plate are fixedly connected to the laser bracket by bolts. By setting the elastic pressing plate and the number of elastic gaskets, the emission angle of the laser beam emitted by the laser can be adjusted to keep it horizontal.

[0047] Furthermore, a device for effectively improving the detection accuracy of a spectrometer also includes an interferometer module 5 and a convergence module 14 fixedly mounted on a base.

[0048] Optimized, a light source cover 10 is fixedly installed on the light source bracket, a light transmission hole is opened on the upper side of the light source cover, a top screw installation hole 15 is opened on the top, an aperture (not shown) is fixedly installed in the light source cover, and an aperture is arranged on the light source cover, and the light beam emitted by the infrared light source is incident on the collimator after being restricted by the aperture. The light source cover also plays a role in protecting the light source, so as to prevent the light source from being affected by external airflow, temperature, etc., which makes the light emission unstable.

[0049] Principle of technical problem:

[0050] 1. The influence of aperture

[0051] The interferometer optical path diagram in the spectrometer can be simplified as Figure 4 As shown, the maximum angle 2θ between the extended light source and the rotation axis can be expressed as:

[0052]

[0053] Where: R is the radius of the extended light source, and f is the focal length of the collimator.

[0054] The solid angle of the extended light source is then:

[0055] Ω=2π(1-cosθ) (2)

[0056] When the interferometer is working, after the moving reflector produces a displacement d, the paraxial beam will produce an additional optical path difference ⊿:

[0057]

[0058] Where: x=2d is the optical path difference caused by the light beam parallel to the rotation axis.

[0059] Within the extended light source incident solid angle Ω, for the incident monochromatic band ν, the intensity of the interference signal is obtained as follows:

[0060]

[0061] Obviously, due to the existence of the extended light source solid angle, the wave number ν of the monochromatic light drifts to a lower wave number, and the drift magnitude is At the same time, the interference signal is affected by the factor Under the influence of the extended light source, the modulation efficiency of the interference signal is:

[0062]

[0063] As the moving reflector moves, When , its modulation efficiency drops to zero. When the optical path difference continues to increase, the interference signal will reverse its phase, so the maximum aperture of the extended light source is:

[0064]

[0065] Where, ν max represents the maximum range of the spectrum, This is the maximum resolution of the instrument.

[0066] On the other hand, if a fixed extended light aperture is considered, the interference signal has a resolution limit, that is, the wave number ν expansion range is:

[0067]

[0068] 2. Impact of offset

[0069] like Figure 5 As shown, it is assumed that the light source is a circular surface light source, radiating monochromatic light with a wave number of ν, and its diameter is 2R. There is an offset error of s between the light source and the ideal position along the direction perpendicular to the rotation axis. The focal length of the collimator is set to f, and r is set to be the distance between any point on the light source and the intersection of the rotation axis and the light source, α = r / f, β = s / f, θ = R / f.

[0070] For a given wave number ν, there will be a certain expansion. When α≤θ-β, it is equivalent to truncating the diameter of the expanded light source to 2(Rs), and the same conclusion as in the analysis of the influence of the aperture is obtained, that is, the limit of resolution is δν=νΩ / 2π. (8)

[0071] When r∈(θ-β,θ+β), the resolution limit of the interference signal is:

[0072]

[0073] 3. The impact of defocus

[0074] When there is a distance Δ between the center of the surface light source and the focus, such as Figure 6 This is the case when Δ>0, that is, the distance between the light source and the collimator is f+Δ. If Δ is small, considering the case when the incident light beam to the interferometer is still parallel, the impact at this time can be simplified to the first and second cases, which will affect the accuracy and resolution of the spectrum.

[0075] Through the above derivation and demonstration, it can be concluded that the position of the light source and the collimation of the light beam are very important for the spectrometer. During the assembly and debugging of the instrument, how to locate the position of the light source is a key issue in the production of the instrument. The existing method of eliminating this influence, due to the processing error and light emitting position error of the light source, as well as the focal length and angle error of the collimator, in the production and manufacturing process of the instrument, no matter how high the processing accuracy of other mechanical parts is and how accurate the positioning is, it is still impossible to make the center position of the light source and the focal position of the collimator completely coincide without fine-tuning.

[0076] Due to the existence of these errors, the spectrum will drift, and there are errors between each spectrometer. When the spectrometer leaves the factory, the spectrometer manufacturer will calibrate the spectrum wavelength. It uses a standard material, such as polystyrene film, carbon monoxide gas, etc., to compare the standard spectrum with the actual measured spectrum, and calibrates the characteristic peak position to achieve the calibration of the spectrum wavelength.

[0077] However, since the shift of the spectral wavelength is a complex function, the wavelength is not only shifted, but also broadened. Moreover, it is not easy to calibrate the entire spectral range. Only a few individual points can be selected for full-band calibration, so this calibration method still has errors. And this error is different for each instrument.

[0078] In the present application, the position arrangement of the infrared light source, laser, interferometer and collimator is the same as that of the existing spectrometer, with a simple structure and relatively low cost. By rotating the collimator, some "useless" stray light of the laser is collected, so that the scattered light emitted by the laser is gathered by the collimator to form a light spot, and the light is the exact position of the focus of the collimator; then the position of the infrared light source is moved so that the center of the infrared light source coincides with the light spot, which is the exact position of the focus of the collimator, and then the position of the infrared light source is fixed to fundamentally solve the collimation problem of the infrared light source, so that the instrument can maintain good consistency in batch production, thereby improving the detection accuracy of the spectrometer.

[0079] In summary, the present invention provides a method and device for effectively improving the detection accuracy of a spectrometer. By collecting "useless" stray light and cooperating with the optical path arrangement and adjustment mechanism, the collimation problem of the infrared light source can be fundamentally solved, so that the instrument can maintain good consistency during batch production and manufacturing, and the detection accuracy of the spectrometer can be improved.

[0080] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for effectively improving the detection accuracy of a spectrometer, characterized in that: The steps include: ---Install the laser of the laser incident module on the laser mounting frame and keep the laser level; ---Install the infrared light source of the infrared light source module on the infrared light source mounting frame; ---Install the collimator of the infrared light source module on the collimator frame; ---Use an imaging plate to observe the position of the collimator focus, so that the horizontal plane where the focus is located coincides with the horizontal plane where the infrared light source is located, and adjust the horizontal position of the infrared light source so that the vertical plane where the focus is located coincides with the vertical plane where the infrared light source is located, and then fix the horizontal position of the infrared light source; ---Adjust the angle of the collimator so that the scattered light emitted by the laser is collected by the collimator and forms a light spot on the intersection of the horizontal plane and the vertical plane where the infrared light source is located. The location of the light spot is the exact location of the focus of the collimator; ---Adjust the longitudinal position of the infrared light source. When the center of the infrared light source completely coincides with the exact position of the collimator focus, fix the longitudinal position of the infrared light source.

2. A device for effectively improving the detection accuracy of a spectrometer, characterized in that: The device includes a base, an infrared light source module, a laser incident module, an interferometer module and a convergence module. The laser incident module includes a laser bracket and a laser. The laser bracket is fixedly installed on the base, and the laser is installed on the laser bracket. The infrared light source module includes a collimator, a collimator seat, a light source bracket, a light source seat and a light source. The collimator seat is fixedly installed on the base, and the collimator is rotatably installed on the collimator seat. The light source bracket is installed on the base and moves laterally along the base. The light source seat is fixedly installed on the light source bracket. The light source is installed on the light source seat and moves longitudinally along the light source seat. A heat insulation bracket is fixedly installed on the base, and a transverse long hole is opened on the light source bracket. The light source bracket and the heat insulation bracket are fixedly connected at the long hole by bolts. The interferometer module and the convergence module are fixedly installed on the base.

3. The device for effectively improving the detection accuracy of a spectrometer according to claim 2, characterized in that: A longitudinal light source mounting hole is provided in the middle of the light source seat, a vertical top screw mounting hole connected to the light source mounting hole is provided in the upper part of the light source seat, the light source passes through the longitudinal light source mounting hole, and a top screw is installed at the vertical top screw mounting hole.

4. The device for effectively improving the detection accuracy of a spectrometer according to claim 2, characterized in that: The collimator seat is an L-shaped structure, including an integrally formed horizontal seat and a vertical seat. The horizontal seat is fixedly mounted on the base, and the middle part of the collimator is rotatably mounted on the vertical seat via a rotating shaft. The collimator is provided with a circle of screw countersunk holes on the periphery of the rotating shaft. The collimator and the vertical seat are connected at the screw countersunk holes via countersunk bolts, and the diameter of the countersunk bolts is smaller than the aperture of the screw countersunk holes.

5. The device for effectively improving the detection accuracy of a spectrometer according to claim 2, characterized in that: There are two laser brackets, the top of the laser bracket is provided with an arc-shaped laser concession, an elastic gasket is installed at the laser concession, an elastic pressing sheet is provided above the laser, and both ends of the elastic pressing sheet are fixedly connected to the laser bracket by bolts.

6. The device for effectively improving the detection accuracy of a spectrometer according to claim 2, characterized in that: A light source cover is fixedly installed on the light source bracket, a light transmission hole is opened on the upper side of the light source cover, a top screw installation hole is opened on the top, and an aperture is fixedly installed in the light source cover.

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