Diffuse reflection spectrum testing device based on adjustable off-axis ellipsoidal mirror

Abstract

The utility model discloses a diffuse reflection spectrum testing device based on an adjustable off-axis ellipsoidal mirror. The diffuse reflection spectrum testing device comprises a shell main body, an observation window, a plane mirror group, a focus plane mirror group, an off-axis ellipsoidal mirror and a sample pool, the plane mirror group comprises a first plane mirror and a second plane mirror; the focus plane reflector group comprises a first focus plane reflector and a second focus plane reflector; the off-axis ellipsoid reflector group comprises a first off-axis ellipsoid reflector and a second off-axis ellipsoid reflector; the first off-axis ellipsoidal reflector and the second off-axis ellipsoidal reflector are both connected with an adjusting device. Compared with a traditional diffuse reflection accessory, the position and angle of the off-axis ellipsoid reflector group can be finely adjusted, the specular reflection component in a sample can be reduced, more diffuse reflection light can be collected, and better luminous flux and better diffuse reflection spectrum can be better obtained.

Description

Technical Field

[0001] This utility model relates to the field of spectral testing devices, and more specifically, to a diffuse reflectance spectral testing device based on an adjustable off-axis ellipsoidal mirror. Background Technology

[0002] Infrared spectroscopy of adsorbed molecules can provide structural information about surface adsorbed species, especially information about the structure of adsorbed species under reaction conditions. In-situ techniques, by real-time monitoring of the dynamic structural evolution of catalysts under different reaction conditions (space, time, temperature, pressure, atmosphere, light, electric field, and magnetic field) (such as surface reconstruction and dynamic migration of active sites), reveal intermediate and transient species in the reaction pathway. In-situ infrared spectroscopy analysis in materials science, chemistry, and environmental engineering can be divided into transmission spectroscopy and reflection spectroscopy. These methods have become essential characterization tools for studying the molecular structure, chemical composition, and surface properties of materials, making material modification research more targeted and enabling the evaluation of actual material performance. By detecting the infrared optical parameters (transmittance, reflectance, and absorptivity) of materials to study their properties, for opaque materials, according to Kirchhoff's thermodynamic laws, at the same wavenumber, the absorptivity equals the emissivity, and the sum of absorptivity, reflectance, and refractive index is 1. For opaque materials, the refractive index is zero, and their emissivity spectrum can also be indirectly obtained.

[0003] Currently, traditional Fourier transform infrared (FTIR) spectrometers measure reflectance spectroscopy, which, compared to transmission spectroscopy, requires the light to be reflected by a mirror to the sample and then by another mirror to the spectrometer's detector. The reflected signal consists of specular reflection and some scattered light from the sample. Furthermore, during sample testing, only the diffusely reflected light that penetrates the sample surface carries sample information; the reflected light from the sample surface does not. Therefore, the practically useful diffuse reflection signal is relatively weak. It is crucial to minimize diffuse reflection signal loss, collect sufficient diffuse reflection light, and minimize surface reflection.

[0004] Compared to transmission spectroscopy, infrared transmission spectroscopy faces more interference during sample preparation, requiring appropriate sample concentration and thickness. Too low a concentration or too thin a sample can lead to inaccurate spectral measurements. Furthermore, pelleting can alter the catalyst morphology, resulting in spectral distortion for non-uniform, scattering samples. Infrared reflectance spectroscopy collects specular and diffuse reflected light from the sample. Although the reflected signal is relatively weak, diffuse reflectance spectroscopy can measure loose powders and is simple to prepare, making it suitable for samples with strong scattering and adsorption. Therefore, infrared diffuse reflectance spectroscopy is generally used to detect heterogeneous catalytic gas-solid reaction changes in samples. Conventional Fourier transform infrared diffuse reflectance spectroscopy accessories typically employ a coaxial symmetrical optical path design, consisting of a plane mirror, an ellipsoidal mirror, a sample cell, an ellipsoidal mirror, and a plane mirror. This design generally results in a strong specular reflection component in the reflected signal, significantly impacting actual in-situ infrared diffuse reflectance spectroscopy measurements and interfering with the actual diffuse reflectance spectrum. Conversely, an off-axis optical path design minimizes the specular reflection component in the reflected signal.

[0005] Therefore, to perform in-situ infrared diffuse reflectance spectroscopy, the optical path must be designed off-axis. Existing devices, once the ellipsoidal mirror is fixed, cannot allow for local adjustments to the optical path based on actual conditions, preventing more incident light from reaching the sample surface. This results in less diffuse reflectance light being collected, leading to a significant impact of specular reflection signals on the diffuse reflectance spectrum. Utility Model Content

[0006] The purpose of this invention is to provide a diffuse reflectance spectroscopy testing device based on an adjustable off-axis ellipsoidal mirror, in order to solve the technical problems existing in the background art.

[0007] This utility model provides a diffuse reflectance spectroscopy testing device based on an adjustable off-axis ellipsoidal mirror, including a housing body, an observation window disposed on the top of the housing body, a plane mirror group located inside the housing body, a focal plane mirror group located on both sides of the plane mirror group, an off-axis ellipsoidal mirror group, and a sample cell located below the off-axis ellipsoidal mirror group.

[0008] The planar reflector group includes a first planar reflector and a second planar reflector; the focal planar reflector group includes a first focal planar reflector and a second focal planar reflector; the off-axis ellipsoidal reflector group includes a first off-axis ellipsoidal reflector and a second off-axis ellipsoidal reflector; both the first off-axis ellipsoidal reflector and the second off-axis ellipsoidal reflector are connected to an adjustment device.

[0009] In a preferred embodiment, the off-axis ellipsoidal reflector assembly is provided with a mounting base on top, and the adjustment device includes an adjustment base fixed to the top of the outer shell, four sets of adjustment screws passing through the adjustment base and contacting the mounting base, the mounting base and the adjustment base being movably connected, and an adjustment spring being provided between the two.

[0010] In a preferred embodiment, the adjusting springs are configured in three groups arranged in a triangular pattern.

[0011] In a preferred embodiment, both the first off-axis ellipsoidal reflector and the second off-axis ellipsoidal reflector are adjusted individually by the adjustment device.

[0012] In a preferred embodiment, a fixed platform is provided inside the outer shell, and a pitch deflection frame for adjusting the angle of the focal plane reflector group is provided on the fixed platform;

[0013] The pitch and yaw frame includes an L-shaped main frame, a yaw adjustment assembly and a pitch adjustment assembly located within the main frame.

[0014] In a preferred embodiment, the deflection adjustment assembly includes a driven wheel, a driving wheel meshing with the driven wheel, and an adjustment rod fixed to the central axis of the driving wheel. The driven wheel is fixedly connected to the main frame and rotatably connected to the fixed platform. The pitch adjustment assembly includes a worm gear structure and a semi-worm gear structure meshing with the worm gear structure.

[0015] In a preferred embodiment, the planar mirror assembly is mounted on a mirror base, and the mirror base is provided with a slot for limiting the position of the planar mirror assembly.

[0016] In a preferred embodiment, a lifting adjustment device is connected to the sample cell. The lifting adjustment device includes a lifting seat, a guide rod, a threaded rod, and a lifting knob. The guide rod passes through the lifting seat and is slidably connected to the lifting seat. The threaded section of the threaded rod is threadedly connected to the lifting seat. The lifting knob is fixedly connected to the threaded rod. A fixing rod threadedly connected to the sample cell is also provided on one side of the lifting seat. The fixing rod passes through the lifting seat.

[0017] The beneficial effects of this utility model's technical solution are:

[0018] Compared to traditional diffuse reflection accessories, this invention can finely adjust the position and angle of the off-axis ellipsoidal mirror assembly, reduce the specular reflection component in the sample, collect more diffuse reflection light, and better obtain better light flux and better diffuse reflection spectrum. Attached Figure Description

[0019] Figure 1This is a schematic diagram of the overall structure of this utility model.

[0020] Figure 2 This is a schematic diagram of the interior of the outer shell of this utility model.

[0021] Figure 3 This is a schematic diagram of the interior of the outer shell of this utility model from another perspective.

[0022] Figure 4 This is a cross-sectional schematic diagram of the adjustment device of this utility model.

[0023] Figure 5 This is a schematic diagram of the pitch and deflection frame of this utility model.

[0024] Explanation of reference numerals in the attached drawings: 1. Outer shell body; 2. Observation window; 3. Flip-up front cover; 4. Circular threaded magnet; 5. Telescopic lens tube; 6. Moving seat; 7. Fixed base; 8. Fixed shaft; 9. First plane mirror; 10. Second plane mirror; 11. First focal plane mirror; 12. Second focal plane mirror; 13. First off-axis ellipsoidal mirror; 14. Second off-axis ellipsoidal mirror; 15. Mirror base; 16. Slot; 17. Mounting seat; 18. Adjusting seat; 19. Adjusting screw; 20. Adjusting spring; 21. Fixed platform; 22. Main frame; 23. Driving wheel; 24. Adjusting rod; 25. Driven wheel; 26. Worm gear structure; 27. Semi-worm gear structure; 28. Lifting seat; 29. ​​Guide rod; 30. Threaded rod; 31. Lifting knob; 32. Fixed rod; 33. Sample cell. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The embodiments of the present invention are given for the purpose of illustration and description, and are not intended to be exhaustive or to limit the present invention to the disclosed forms. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical applications of the present invention, and to enable those skilled in the art to understand the present invention and design various embodiments with various modifications suitable for a particular purpose.

[0026] like Figures 1-5 As shown, the present invention provides a diffuse reflectance spectroscopy testing device based on an adjustable off-axis ellipsoidal mirror, including a housing body 1, an observation window 2 disposed on the top of the housing body 1, a plane mirror group located inside the housing body 1, a focal plane mirror group located on both sides of the plane mirror group, an off-axis ellipsoidal mirror group, and a sample cell 33 located below the off-axis ellipsoidal mirror group.

[0027] The outer shell 1 has a flip-up front cover 3 near the sample cell 33. The flip-up front cover 3 can rotate and is fixed by a circular threaded magnet 4. Telescopic lens tubes 5 are also provided on both sides of the sample platform, which can be adjusted according to different spectrometer signals to avoid external light interference during testing. The bottom of the outer shell 1 is provided with a movable seat 6 and a fixed base 7 with a sliding groove. The outer shell 1 can be moved on the fixed base 7 by pushing the fixed shaft 8.

[0028] The planar reflector group includes a first planar reflector 9 and a second planar reflector 10; the focal plane reflector group includes a first focal plane reflector 11 and a second focal plane reflector 12; the off-axis ellipsoidal reflector group includes a first off-axis ellipsoidal reflector 13 and a second off-axis ellipsoidal reflector 14; both the first off-axis ellipsoidal reflector 13 and the second off-axis ellipsoidal reflector 14 are connected to adjustment devices.

[0029] In this scheme, the beam path is as follows: infrared light exits through the off-axis parabolic mirror within the infrared spectrometer, then sequentially passes through the first plane mirror 9, the first focal plane mirror 11, the first off-axis ellipsoidal mirror 13, the second off-axis ellipsoidal mirror 14, the second focal plane mirror 12, and the second plane mirror 10. It then enters the off-axis parabolic mirror within the spectrometer, and finally, through the off-axis parabolic mirror, enters the detector to collect infrared test data. The infrared beam is incident on the sample surface at an angle of 35°-45°, which is the range for obtaining the strongest infrared reflectance spectrum from the sample. This maximizes the optimization of infrared light reflection and collection, thereby improving the intensity of the infrared detection light.

[0030] In this scheme, the convergent detection beam emitted from the spectrometer's output port is reflected by the first plane mirror 9 to the first focal plane mirror 11, which is the first focal point F1 of the first off-axis ellipsoidal mirror 13. The first focal plane mirror 11 reflects the convergent detection beam back to the first off-axis ellipsoidal mirror 13, which then converges the detection beam to its common focal point with the second off-axis ellipsoidal mirror 14, which is the position of the sample cell 33, i.e., F2. The beam is then collected by the second off-axis ellipsoidal mirror 14 and sent to the second focal plane mirror 12, which is the second focal point of the second off-axis ellipsoidal mirror 14, i.e., F3. The beam is then reflected by the second focal plane mirror 12 to the second plane mirror 10, and then reflected by the second plane mirror 10 into the off-axis parabolic mirror of the spectrometer. The spectrometer then collects the data, realizing in-situ online reaction monitoring.

[0031] The aforementioned position point F1 is the focal point of the first off-axis ellipsoidal mirror 13; position point F2 is the common focal point of the first off-axis ellipsoidal mirror 13 and the second off-axis ellipsoidal mirror 14; and position point F3 is the focal point of the second off-axis ellipsoidal mirror 14. Since different spectrometers have different focal points and focal lengths within their sample cells 33, the infrared light collected by the off-axis ellipsoidal mirror group may not reach the center of the sample surface. Furthermore, it is necessary to optimize the infrared diffuse reflection signal collected by the off-axis ellipsoidal mirror group. Therefore, the position of the off-axis ellipsoidal mirror group is fine-tuned using an adjustment device to meet the detection requirements.

[0032] The off-axis ellipsoidal reflector assembly is topped with a mounting base 17. The adjustment device includes an adjustment seat 18 fixed to the top of the outer casing and four sets of adjustment screws 19 passing through the adjustment seat 18 and contacting the mounting base 17. The mounting base 17 is movably connected to the adjustment seat 18, and an adjustment spring 20 is provided between them. The adjustment spring 20 is configured in three sets arranged in a triangle, with both sides of the adjustment spring fixed to the mounting base and the adjustment seat, respectively.

[0033] In the above scheme, four sets of adjusting screws 19 are located at the four corners of the adjusting base 18. The adjusting screws 19 are in contact with the mounting base 17. By turning the corresponding adjusting screws 19, the adjusting screws 19 can press against the mounting base 17 and move. Because of the presence of three sets of adjusting springs 20, the mounting base 17 can move and reset flexibly, thereby achieving effective fine-tuning of the position of the off-axis ellipsoidal reflector group, thereby adjusting the position of the light spot and optimizing the amount of diffuse light collected. The first off-axis ellipsoidal reflector 13 and the second off-axis ellipsoidal reflector 14 are both adjusted individually by the adjusting device, and their adjustment is not interfered with each other, resulting in high adjustment flexibility. Of course, in addition to adjusting the adjusting screws 19 manually, the adjusting screws 19 can also be adjusted by rotating them through a motor structure. After the position and angle of the first focal plane reflector 11 and the second focal plane reflector 12 are adjusted, the attitude of the off-axis ellipsoidal reflector can be more accurately controlled through the coupling of the motor control program and the signal monitoring system of the spectrometer, so as to better optimize the diffuse light collection system.

[0034] The main body 1 of the outer casing is provided with a fixed platform 21, on which a pitch deflection frame for adjusting the angle of the focal plane mirror assembly is provided. The pitch deflection frame includes an L-shaped main frame 22, a deflection adjustment component and a pitch adjustment component located within the main frame 22. The deflection adjustment component and the pitch adjustment component are used to adjust the deflection angle and pitch angle of the focal plane mirror assembly, respectively. The first focal plane mirror 11 and the second focal plane mirror 12 can be adjusted independently.

[0035] The deflection adjustment assembly includes a driven wheel 25, a driving wheel 23 meshing with the driven wheel 25, and an adjustment rod 24 fixed to the central axis of the driving wheel 23. The driven wheel 25 is fixedly connected to the main frame 22 and rotatably connected to the fixed platform 21. The pitch adjustment assembly includes a worm gear structure 26 and a semi-worm gear structure 27 meshing with the worm gear structure 26.

[0036] During deflection adjustment, rotating the adjusting rod 24 drives the driving wheel 23 to rotate, which in turn drives the driven wheel 25 meshing with it to rotate. Since the driven wheel 25 is fixed to the main frame 22, it drives the main frame 22 to rotate, thereby achieving deflection adjustment of the focal plane mirror assembly. During pitch adjustment, rotating the worm gear structure 26 drives the meshing semi-worm gear structure 27 to rotate. Setting the worm gear structure to half-rotation achieves the pitch adjustment function. The focal plane mirror assembly is mounted on the semi-worm gear structure 27, and rotation of the semi-worm gear structure 27 achieves pitch adjustment of the focal plane mirror assembly.

[0037] The planar reflector assembly is mounted on the reflector base 15, and the reflector base 15 is provided with a slot 16 for limiting the planar reflector assembly. The first planar reflector 9 and the second planar reflector 10 are symmetrically mounted on the reflector base 15.

[0038] The sample cell 33 is connected to a lifting and adjusting device, which allows the sample cell 33 to be raised and lowered to facilitate the placement and positioning of other auxiliary equipment. The lifting and adjusting device includes a lifting base 28, a guide rod 29, a threaded rod 30, and a lifting knob 31. The guide rod 29 passes through the lifting base 28 and is slidably connected to it. The threaded section of the threaded rod 30 is threadedly connected to the lifting base 28. The lifting knob 31 is fixedly connected to the threaded rod 30. A fixing rod 32, which is threadedly connected to the sample cell 33, is also provided on one side of the lifting base 28 and passes through the lifting base 28.

[0039] In the above scheme, the lifting seat 28 and the sample cell 33 are first inserted and limited, and then the lifting seat 28 and the sample cell 33 are fixed by the fixing rod 32. The above installation method facilitates the disassembly of the sample cell 33. When adjusting the lifting position, the lifting seat 28 can be raised and lowered by turning the lifting knob 31. Because of the presence of the guide rod 29, the lifting seat 28 can move linearly, thereby driving the sample cell 33 connected to it to move synchronously and stably.

[0040] Compared to traditional diffuse reflection accessories, this invention can finely adjust the position and angle of the off-axis ellipsoidal mirror assembly, reduce the specular reflection component in the sample, collect more diffuse reflection light, and better obtain better light flux and better diffuse reflection spectrum.

[0041] Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. All other embodiments obtained by those skilled in the art and related fields based on the embodiments of this utility model without creative effort should fall within the protection scope of this utility model. Structures, devices, and operating methods not specifically described and explained in this utility model, unless otherwise specified or limited, shall be implemented according to conventional means in the art.

Claims

1. A diffuse reflectance spectral testing device based on an adjustable off-axis ellipsoidal mirror, characterized in that: It includes a housing body, an observation window disposed on the top of the housing body, a plane mirror assembly located inside the housing body, a focal plane mirror assembly located on both sides of the plane mirror assembly, an off-axis ellipsoidal mirror assembly, and a sample cell located below the off-axis ellipsoidal mirror assembly; The planar mirror assembly includes a first planar mirror and a second planar mirror; the focal planar mirror assembly includes a first focal planar mirror and a second focal planar mirror; the off-axis ellipsoidal mirror assembly includes a first off-axis ellipsoidal mirror and a second off-axis ellipsoidal mirror. Both the first off-axis ellipsoidal reflector and the second off-axis ellipsoidal reflector are connected to adjustment devices.

2. The diffuse reflectance spectral testing device based on an adjustable off-axis ellipsoidal mirror according to claim 1, characterized in that: The off-axis ellipsoidal reflector assembly is provided with a mounting base on top. The adjustment device includes an adjustment base fixed to the top of the outer shell, four sets of adjustment screws passing through the adjustment base and contacting the mounting base, the mounting base and the adjustment base being movably connected, and an adjustment spring being provided between them.

3. The diffuse reflectance spectral testing device based on an adjustable off-axis ellipsoidal mirror according to claim 2, characterized in that: The adjusting springs are configured in three groups and arranged in a triangular pattern.

4. The diffuse reflectance spectral testing device based on an adjustable off-axis ellipsoidal mirror according to claim 2, characterized in that: The first off-axis ellipsoidal reflector and the second off-axis ellipsoidal reflector are both adjusted individually by the adjustment device.

5. The diffuse reflectance spectral testing device based on an adjustable off-axis ellipsoidal mirror according to claim 1, characterized in that: A fixed platform is provided inside the main body of the outer shell, and a pitch deflection frame for adjusting the angle of the focal plane reflector group is provided on the fixed platform. The pitch and yaw frame includes an L-shaped main frame, a yaw adjustment assembly and a pitch adjustment assembly located within the main frame.

6. The diffuse reflectance spectral testing device based on an adjustable off-axis ellipsoidal mirror according to claim 5, characterized in that: The deflection adjustment assembly includes a driven wheel, a driving wheel meshing with the driven wheel, and an adjustment rod fixed to the central axis of the driving wheel. The driven wheel is fixedly connected to the main frame and rotatably connected to the fixed platform. The pitch adjustment assembly includes a worm gear structure and a semi-worm gear structure meshing with the worm gear structure.

7. The diffuse reflectance spectral testing device based on an adjustable off-axis ellipsoidal mirror according to claim 1, characterized in that: The planar mirror assembly is mounted on a mirror base, and the mirror base is provided with a slot for limiting the position of the planar mirror assembly.

8. The diffuse reflectance spectral testing device based on an adjustable off-axis ellipsoidal mirror according to claim 1, characterized in that: The sample cell is connected to a lifting adjustment device, which includes a lifting base, a guide rod, a threaded rod, and a lifting knob. The guide rod passes through the lifting base and is slidably connected to it. The threaded section of the threaded rod is threadedly connected to the lifting base. The lifting knob is fixedly connected to the threaded rod. A fixing rod threadedly connected to the sample cell is also provided on one side of the lifting base. The fixing rod passes through the lifting base.

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