Biconvex lens type diffuse reflection accessory

Abstract

The invention relates to the technical field of instrument analysis, and particularly discloses a biconvex lens type diffuse reflection accessory which comprises a shell, a sample table, a biconvex lens dome and two sets of reflector assemblies, light beam channel holes are symmetrically formed in the two sides of the shell, the sample table is fixed in the shell through a positioning pin, and the biconvex lens dome and the sample table form a closed cavity. Convex lens window sheets made of zinc selenide / potassium bromide are symmetrically arranged on the two sides of the substrate; the reflector assembly is composed of an irregular trapezoid base and a wedge-shaped base which are installed on the bottom face and the top face of the shell, the irregular trapezoid base and the wedge-shaped base bear gold-plated plane reflectors respectively, two times of total reflection and focusing of incident light beams are achieved, and diffuse reflection light on the surface of a sample is recycled. Compared with the prior art, the device has the advantages of low cost, small size, simplicity and convenience in operation and maintenance and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of instrumental analysis, and particularly to a double convex lens type diffuse reflection accessory. Background Art

[0002] Diffuse reflection is one of the ways of light reflection, which usually occurs on rough surfaces. When light irradiates an uneven surface, the irregular structures on the surface cause the incident light to be reflected at different angles, so that the reflected light is evenly distributed in all directions. It is often used in optical instruments and sensors, for example, to measure the surface characteristics or distance of an object through diffuse reflection.

[0003] In catalyst research, diffuse reflection infrared and diffuse reflection ultraviolet-visible spectroscopy are two commonly used characterization techniques.

[0004] Diffuse reflection infrared: When infrared light irradiates the catalyst surface, part of the light is absorbed, and the remaining light is reflected back to the detector. By analyzing the reflection spectrum, information about the adsorbed substances, active sites on the catalyst surface, and catalytic reaction intermediates can be obtained. It is applicable to the analysis of surface chemistry, reaction mechanism, and catalyst performance, especially has important application value for gas-solid phase reactions and catalytic processes under high-temperature environments.

[0005] Diffuse reflection ultraviolet-visible spectroscopy: In the ultraviolet and visible light ranges, the absorption characteristics of the catalyst can provide information about its electronic structure, band gap, light absorption performance, and catalytic activity. When ultraviolet-visible light irradiates the catalyst surface, the light is partially absorbed, and the remaining light is reflected and received by the detector, thereby obtaining the absorption spectrum of the catalyst. It has a wide range of applications in the field of photocatalysis and can help reveal the reaction mechanism of the catalyst through spectral changes.

[0006] Traditional commercial diffuse reflection sample cells usually achieve signal collection and uniform distribution of light through an integrating sphere accessory. Although the integrating sphere can improve the uniformity of light through multiple reflections, each reflection will bring a certain amount of energy loss, resulting in signal intensity attenuation. In addition, the integrating sphere is large in volume. In the design of sample cells (especially in-situ sample cells), integrating the integrating sphere requires a trade-off in spatial layout and optical path. At the same time, the manufacturing of the integrating sphere itself and the highly reflective materials (such as gold, aluminum, etc.) coated on its inner surface will significantly increase the cost. Especially for the gold-plated surface, not only the material cost is high but also it is easily damaged, further increasing the maintenance cost. Therefore, it is of great significance to develop a new type of diffuse reflection accessory with a small volume, concentrated signal, and low cost by improving the optical path design. Summary of the Invention

[0007] The object of the present invention is to overcome the defects of the above-mentioned existing technologies and provide a double-convex lens type diffuse reflection accessory. By improving the optical path design, a new type of diffuse reflection accessory with small volume, concentrated signal and low cost is developed.

[0008] The object of the present invention can be achieved by the following technical solutions:

[0009] The present invention provides a double-convex lens type diffuse reflection accessory, including a housing, a sample stage, a double-convex lens dome, and two sets of mirror assemblies. Specifically:

[0010] Beam passage holes are symmetrically arranged on the left and right sides of the housing;

[0011] The sample stage is arranged in the housing;

[0012] The double-convex lens dome is arranged on the sample stage. The double-convex lens dome and the upper surface of the sample stage form a sealed cavity. Convex lens window pieces are symmetrically arranged on the double-convex lens dome along the beam passage direction;

[0013] The two sets of mirror assemblies include:

[0014] Irregular trapezoidal mirror bases arranged on the inner bottom surfaces on both sides of the housing. A first plane mirror is arranged on the trapezoidal mirror base,

[0015] Wedge-shaped mirror bases arranged on the inner top surfaces on both sides. A second plane mirror is arranged on the wedge-shaped mirror base,

[0016] The incident beam is successively totally reflected by the beam passage hole on one side, the first plane mirror, and the second plane mirror, and refracted and focused on the sample surface through the convex lens window piece on one side. The generated diffuse reflection light is refracted by the convex lens window piece on the other side and finally totally reflected by the second plane mirror and the first plane mirror to the beam passage hole on the other side.

[0017] Furthermore, a first positioning pin is arranged on the inner bottom surface of the housing.

[0018] Furthermore, a positioning hole matching the first positioning pin is arranged on the lower surface of the sample stage to fix the sample stage.

[0019] Furthermore, the double-convex lens dome is a hemispherical shell structure, and a connection hole is arranged at the bottom of the double-convex lens dome.

[0020] Furthermore, an annular sealing groove is arranged on the upper surface of the sample stage. A second positioning pin is arranged in the middle of the annular sealing groove. A sample groove is arranged in the middle of the second positioning pin. The sample to be tested is placed on the sample groove.

[0021] Furthermore, an internal thread is arranged on the inner wall surface of the outer ring of the annular sealing groove;

[0022] The outer wall surface of the second positioning pin forms the inner ring of the annular sealing groove, and a sealing ring is provided on the outer wall surface of the second positioning pin;

[0023] The outer edge of the bottom of the bi-convex lens dome is provided with an external thread that matches the internal thread on the outer ring of the annular sealing groove;

[0024] The connection hole at the bottom of the bi-convex lens dome matches the second positioning pin, and the sealing ring is clamped between the outer wall surface of the second positioning pin and the inner wall surface of the connection hole.

[0025] Further, the surfaces of the first plane mirror and the second plane mirror are coated with a gold film layer, the coating thickness is 50 - 200 nm, and the reflectivity is ≥ 98%.

[0026] Further, the convex lens window is made of zinc selenide material or potassium bromide material.

[0027] Further, the cross-section of the irregular trapezoidal mirror base is a right trapezoidal block with a groove or hollow in the middle;

[0028] The wedge-shaped mirror base is a block with a right trapezoidal cross-section.

[0029] The housing is provided with a gas access hole and a gas discharge hole. The gas access hole is connected to an external gas supply device, and the gas discharge hole is connected to an external collection device. At the same time, both the gas access hole and the gas discharge hole are connected to the bi-convex lens dome through pipelines, so that the reaction gas can enter the bi-convex lens dome from the gas access hole and be discharged through the gas discharge hole.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] Compared with the commercial integrating sphere type diffuse reflection accessory, the bi-convex lens type diffuse reflection accessory of the present invention only requires four plane mirrors and two convex lenses, and this accessory can effectively collect sample information in both non-in-situ sample cells and in-situ sample cells. Due to the reduction in the number of parts, its overall volume is significantly reduced, the maintenance cost is greatly reduced, and the operation is more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic structural diagram of the bi-convex lens type diffuse reflection accessory in the present invention;

[0033] Figure 2 is a schematic optical path diagram of the bi-convex lens type diffuse reflection accessory;

[0034] Figure 3 is a top view of the sample stage;

[0035] Figure 4 Exploded view of a double convex lens dome;

[0036] Figure 5 CO-DRIFTS infrared spectrum of 20% wt CuAl catalyst.

[0037] 1. Wedge-shaped mirror base; 2. Convex lens window; 3. Sample stage; 4. Irregular trapezoidal mirror base; 5. Double convex lens dome; 6. Outer shell; 7. Beam channel hole; 8. Annular sealing groove; 9. Second positioning pin; 10. Sample groove; 11. First positioning pin. Specific implementation mode

[0038] Overall, the present invention relates to a novel double convex lens type diffuse reflection accessory. The common diffuse reflection accessories on the market are based on the integrating sphere optical path, while this diffuse reflection accessory is innovatively based on the convex lens optical path. The principle of collecting sample information is as follows: The beam first exits horizontally from the spectrometer, and then undergoes two total internal reflections on two gold-plated mirrors to change the direction of the beam so that it can be incident on the convex lens window at an appropriate angle. Subsequently, the beam refracts at the convex lens window and finally converges on the surface of the sample. At this time, the beam undergoes diffuse reflection with the solid sample to be detected at the convergence point, thus carrying information about the interaction with the molecules inside the sample. Finally, the diffuse reflection light carrying rich sample structure and tissue information refracts at another convex lens window. The positions of the two convex lenses are precisely designed so that their focal lengths coincide on the surface of the solid sample. Therefore, the divergent diffuse reflection light can become parallel light, and then through two total internal reflections, the direction of the beam is changed so that it can smoothly enter the detector of the spectrometer horizontally, facilitating the acquisition of relevant information about the sample. Compared with commercial integrating sphere type diffuse reflection accessories, this novel diffuse reflection accessory has the advantages of low cost, small volume, simple operation and maintenance.

[0039] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Features such as component models, material names, connection structures, control methods, algorithms, etc. that are not clearly stated in this technical solution are regarded as common technical features disclosed in the prior art.

[0040] Example 1

[0041] See Figure 1 , the double convex lens type diffuse reflection accessory in this embodiment includes the following core components:

[0042] Outer shell 6:

[0043] Beam channel holes 7 are symmetrically opened on the left and right, and the aperture matches the exit spot of the spectrometer;

[0044] Gas access holes and discharge holes are reserved at the top to connect to the external gas path system.

[0045] Sample stage 3:

[0046] See Figure 3 , the lower surface is provided with positioning holes, which are inserted into the first positioning pins 11. There are 2 first positioning pins 11 provided at the bottom of the fixed housing 6 for precise positioning of the sample stage 3. The sample stage can be installed and fixed in the housing 6 through the positioning holes at the bottom of the sample stage;

[0047] The upper surface is designed with an annular sealing groove 8, which houses the second positioning pin 9 and the sample groove 10;

[0048] The outer ring of the annular sealing groove is provided with internal threads, which are screwed with the external threads on the outer edge of the bottom of the double convex lens dome 5.

[0049] Double convex lens dome 5:

[0050] A hemispherical shell, symmetrically embedded with convex lens windows 2 of zinc selenide / potassium bromide on the left and right;

[0051] The bottom connection hole is nested with the second positioning pin 9 of the sample stage, and airtightness is achieved through a sealing ring;

[0052] A closed gas chamber is formed inside the dome and the sample stage, and reaction gases can be introduced for in-situ detection.

[0053] Mirror assembly:

[0054] An irregular trapezoidal mirror base 4: Installed on the inner bottom surface of the housing, carrying a first plane mirror with a gold coating and a reflectivity of ≥98%, used for the primary turning of the horizontal beam;

[0055] A wedge-shaped mirror base 1: Installed on the inner top surface of the housing, carrying a second plane mirror to complete the secondary turning of the beam and signal recovery.

[0056] The incident beam is successively totally reflected by the beam channel hole 7 on one side, the first plane mirror, and the second plane mirror, and is refracted and focused on the sample surface through the convex lens window 2. The generated diffuse reflected light is refracted by the convex lens window 2 on the other side and finally totally reflected by the second plane mirror and the first plane mirror to the beam channel hole 7 on the other side, see Figure 2 .

[0057] The arrangement of this mirror ensures that the beam emitted by the spectrometer can smoothly enter the sample stage, obtain rich information on the sample surface, and transmit this information back to the analytical instrument.

[0058] The convex lens window 2 includes a transparent sheet made of zinc selenide / potassium bromide material and a threaded collar provided around the transparent sheet. The threaded collar is sleeved on the outer periphery of the double convex lens dome 5, and the convex lens window 2 is tightly installed on the body of the double convex lens dome 5 through the threaded collar, see Figure 4 .

[0059] The surfaces of the first plane mirror and the second plane mirror are coated with a gold film layer, and the coating thickness is 50 - 200 nm, with a reflectivity ≥ 98%. The convex lens window is made of zinc selenide or potassium bromide. The cross-section of the irregular trapezoidal mirror base 4 is a right trapezoidal block with a groove or hollow in the middle.

[0060] The wedge-shaped mirror base 1 is a block with a right trapezoidal cross-section.

[0061] The housing 6 is provided with a gas inlet hole and a gas outlet hole. The gas inlet hole is connected to an external gas supply device, and the gas outlet hole is connected to an external collection device. At the same time, both the gas inlet hole and the gas outlet hole are connected to the double convex lens dome 5 through pipelines, so that the reaction gas can enter the double convex lens dome 5 from the gas inlet hole and be discharged through the gas outlet hole.

[0062] Application Example 1

[0063] Installation of the mirror assembly

[0064] Fix two irregular trapezoidal mirror bases 4 on both sides of the inner bottom surface of the housing 6 through positioning bolts, and the inclined surface of the base forms a 45° angle with the horizontal plane. Coat high-temperature resistant silica gel in the base groove, embed a gold-plated plane mirror (gold film thickness 150 nm ± 10 nm, reflectivity ≥ 99%), and let it stand and cure for 24 hours. Similarly, install wedge-shaped mirror bases 1 on both sides of the inner top surface of the housing, with its inclined surface forming a 30° angle with the horizontal plane, and embed gold-plated mirrors of the same specification.

[0065] Positioning of the sample stage

[0066] Align the positioning hole on the lower surface of the sample stage 3 with the first positioning pin 11 at the bottom of the housing, and apply vertical pressure until it is fully engaged. Lay a circular potassium bromide tablet with a diameter of 5 mm in the sample groove 10 as the sample carrier, and the surface roughness Ra ≤ 0.8 μm.

[0067] Sealing of the double convex lens dome

[0068] Insert a fluororubber O-ring (wire diameter 1.5 mm) into the annular sealing groove 8 of the sample stage, align the connection hole at the bottom of the double convex lens dome 5 with the second positioning pin 9, rotate the dome so that its external thread meshes with the internal thread in the annular sealing groove, and apply a torque of 2 N·m to tighten it to form a sealed cavity that can withstand a gas pressure of 0.5 MPa.

[0069] Optical path calibration verification

[0070] Use a 635 nm laser light source to enter the left beam channel hole 7, and observe that the light spot is focused on the center of the sample groove after being refracted by the mirror assembly, and the light spot diameter ≤ 0.5 mm. Adjust the angle fine-tuning screw of the wedge-shaped mirror base (adjustment accuracy ±0.1°) so that the deviation of the returned beam from the axis of the right channel hole is less than 0.2 mm.

[0071] The following is in-situ infrared diffuse reflectance spectroscopy detection (taking CO adsorption as an example).

[0072] Catalyst pretreatment

[0073] Press the CuO-Al 2 O 3 (The loading amount of CuO is 20 wt%) catalyst powder into a tablet and place it in the sample groove 10. Pass pure Ar through the gas access hole at a flow rate of 30 ml / min, and heat the system to 150 °C and keep it for 30 min to remove moisture, and then cool it back to room temperature. Subsequently, switch the gas path to 10% H 2 , increase the temperature program to 300 °C, and keep it at a constant temperature for 60 min to reduce the catalyst. After the reduction is completed, switch back to pure Ar gas and lower the temperature to room temperature. Finally, switch the gas path to 0.05 wt% CO gas, and after passing it for 30 min, perform infrared diffuse reflectance spectroscopy analysis on the catalyst to obtain information on the surface of the Cu-Al 2 O 3 catalyst, as Figure 5 shown.

[0074] The above description of the embodiments is to enable those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative efforts. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present invention according to the disclosure of the present invention should be within the protection scope of the present invention.

Claims

1. A double convex lens diffuse reflection accessory, characterized in that: include: A housing (6), wherein the housing (6) is provided with beam passage holes (7) in a bilaterally symmetrical manner; A sample stage (3) is arranged in the housing (6); A double convex lens dome (5) is arranged on the sample stage (3), the double convex lens dome (5) and the upper surface of the sample stage (3) form a closed cavity, and convex lens windows (2) are symmetrically arranged on the double convex lens dome (5) along the direction of the light beam channel; Two sets of reflector assemblies, including: An irregular trapezoidal reflector base (4) is arranged on the inner bottom surfaces of both sides of the housing (6), wherein a first plane reflector is arranged on the trapezoidal reflector base (4). A wedge-shaped reflector base (1) is arranged on the inner top surfaces of both sides of the housing (6), and a second plane reflector is arranged on the wedge-shaped reflector base (1). The incident light beam is totally reflected by the light beam passage hole (7) on one side, the first plane reflector, and the second plane reflector in sequence, and finally refracted and focused on the sample surface by the convex lens window (2) on one side, and the generated diffuse reflected light is refracted by the convex lens window (2) on the other side, and totally reflected by the second plane reflector and the first plane reflector to the light beam passage hole (7) on the other side.

2. A double convex lens diffuse reflection accessory according to claim 1, characterized in that: The inner bottom surface of the outer shell (6) is provided with a first positioning pin (11).

3. A double convex lens diffuse reflection accessory according to claim 2, characterized in that: The lower surface of the sample stage (3) is provided with a positioning hole matching the first positioning pin (11), thereby achieving the fixation of the sample stage (3).

4. The double convex lens diffuse reflection accessory according to claim 1, characterized in that: The double convex lens dome (5) is a hemispherical shell structure, and a connection hole is provided at the bottom of the double convex lens dome (5).

5. A double convex lens diffuse reflection accessory according to claim 4, characterized in that: The upper surface of the sample stage (3) is provided with an annular sealing groove (8), a second positioning pin (9) is provided in the middle of the annular sealing groove (8), a sample groove (10) is provided in the middle of the second positioning pin (9), and a sample to be tested is placed on the sample groove (10).

6. A double convex lens diffuse reflection accessory according to claim 5, characterized in that: The inner wall surface of the outer ring of the annular sealing groove (8) is provided with an internal thread; The outer wall surface of the second positioning pin (9) forms the inner ring of the annular sealing groove (8), and a sealing ring is provided on the outer wall surface of the second positioning pin (9); The outer edge of the bottom of the biconvex lens dome (5) is provided with an external thread matching the internal thread on the outer ring of the annular sealing groove (8); The connecting hole at the bottom of the double convex lens dome (5) matches the second positioning pin (9), and the sealing ring is clamped between the outer wall surface of the second positioning pin (9) and the inner wall surface of the connecting hole.

7. The double convex lens diffuse reflection accessory according to claim 1, characterized in that: The surfaces of the first plane reflector and the second plane reflector are plated with a gold film layer, the thickness of the layer is 50-200nm, and the reflectivity is ≥98%.

8. The double convex lens diffuse reflection accessory according to claim 1, characterized in that: The convex lens window is made of zinc selenide or potassium bromide.

9. The double convex lens diffuse reflection accessory according to claim 1, characterized in that: The cross section of the irregular trapezoidal reflector base (4) is a right-angled trapezoidal block with a groove or a hollow in the middle; The wedge-shaped reflector base (1) is a block with a right-angled trapezoidal cross section.

10. The double convex lens diffuse reflection accessory according to claim 1, characterized in that: The housing (6) is provided with a gas inlet hole and a gas outlet hole, wherein the gas inlet hole is connected to an external gas supply device, and the gas outlet hole is connected to an external collection device. At the same time, the gas inlet hole and the gas outlet hole are both connected to the double convex lens dome (5) through a pipeline, so that the reaction gas can enter the double convex lens dome (5) from the gas inlet hole and be discharged through the gas outlet hole.

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