Variable incident angle ATR accessory

Abstract

The ATR accessory is characterized in that an upper cover, a gasket, a hemispherical ATR crystal, an upper bearing, a concave mirror, a lower bearing, a spring, a convex mirror and a base are connected, the distance between the upper bearing, the concave mirror, the lower bearing, the spring, the convex mirror and the base is adjusted through a fine thread screw, and a rotary mirror bracket with a shading sheet is assembled on a light-in window on the side face of the accessory and connected with the light-in window end of the lower bearing of the accessory. The lower part of the lower bearing is connected with the convex mirror; the lower part of the convex mirror is connected with the base; the upper part of the lower bearing is connected with the concave mirror; the upper part of the concave mirror is connected with the upper bearing; the fine thread screw can adjust the up-and-down position of the accessory and the front-and-back and left-and-right position between the concave mirror and the convex mirror, and the attenuated total reflection angle can be changed by rotating the mirror bracket to adjust the light path shielding part of the anti-dazzling screen, so that the incidence depth is changed.

Description

Technical Field

[0001] The invention relates to an ATR accessory with a variable incident angle, belonging to the technical field of marine infrared optical detection. Background Art

[0002] Qualitative analysis is necessary to analyze tiny pollutants or foreign objects that often appear in the ocean, or to find the source of trace pollutants. The sample volume is often small and uneven (such as a non-homogeneous solid mixture), so it is crucial to select a method that can accurately lock the different depths of the micro-area for qualitative detection of pollutants at multiple depths. For traditional detection methods of layered trace samples, such as controlling the incident angle by adjusting the reflector, the adjustment structure is complex, and it is difficult to ensure the consistency of the two reflectors for the incident and outgoing, which can easily cause energy loss.

[0003] In recent years, variable incident angle ATR accessories based on infrared attenuated total reflection have developed rapidly. Since the early 1980s, microscopy technology has been applied to Fourier transform infrared spectrometers, and ATR-FTIR instruments have been born. In 2005, Y Suzuki et al. used ATR-FTIR to conduct in-situ UHV infrared measurements, which made the analysis of micro-area components convenient and fast, with a detection sensitivity of several nanograms (ng) and a measurement area diameter of several microns. In 2010, Hbich A et al. used different wavelengths of ATR-FTIR to produce evanescent waves with different penetration depths to study the selective absorption of chiral surfactants at the solid-liquid interface. In 2015, Wrobel.TP et al. obtained different penetration depths by changing the incident angle in ATR-FTIR, and then detected the sample, providing a preliminary basis and experiment for the generation of variable incident angle ATR accessories. In 2017, Lu Zhenyu and others conducted principal component analysis on non-homogeneous blood-smeared cotton samples under different pressures and concluded that different pressure levels would change the effective sampling depth and volume. This laid a certain foundation for the pressure sensor of the ATR accessory to control the appropriate sampling depth and volume.

[0004] For commercial ATR-FTIR accessories that can test sample information at different depths, the price is relatively high, and there are many optical path components. Usually, a rotatable symmetrical reflector or a pressure device is used. For a rotatable symmetrical reflector, the incident depth is changed by changing the angle of the reflector. The symmetrical reflector needs to have the same rotation angle, otherwise it will cause energy loss.

[0005] Therefore, at this stage, it is of great significance to develop a set of low-cost, high-precision, and simplified variable-incident-angle ATR accessories for detecting water pollution components at different depths. Summary of the invention

[0006] In view of the deficiencies of the prior art, the present invention provides a variable incident angle ATR accessory, which uses an attenuated total reflection optical path and a partially shielded rotating mirror frame in the incident light area to achieve a certain range of incident angle adjustment.

[0007] The variable incident angle ATR accessory comprises an upper cover, a gasket, a hemispherical ATR crystal, an upper support, a concave mirror, a lower support, a spring, a convex mirror, and a base from top to bottom, and the distances between them are adjusted by a fine-pitch screw. The side light entrance window of the accessory is equipped with a rotating mirror frame with a light shielding sheet.

[0008] The rotating mirror frame with shielding lens is connected to the light entrance window end of the lower support of the accessory, facing the incident light source of the spectrometer, and the light exit window end of the lower support of the accessory faces the detection window of the spectrometer. The lower support is connected to the convex mirror, the lower part of the convex mirror is connected to the base, the upper part of the lower support is connected to the concave mirror, the upper part of the concave mirror is connected to the upper support, the upper support carries a hemispherical ATR crystal, and the upper part is fixed by the upper cover and the gasket. The base is equipped with a fine-pitch screw with a stroke of 6mm, which is used to support and adjust the height of the convex mirror; the lower support and the convex mirror are connected to the spring through a fine-pitch screw with a stroke of 13mm, and the fine-pitch screw is used to adjust the front-to-back distance between the lower support and the concave mirror. Two springs with a stroke of 15.5mm are used to ensure parallel movement; the lower support and the concave mirror are connected through two fine-pitch screws with a stroke of 13nmm, which are used to adjust the left-right distance between the concave mirror and the lower support. Through the above-mentioned screw, the up and down position adjustment of the accessory relative to the optical path and the front, back, left and right position adjustment between the concave mirror and the convex mirror can be achieved.

[0009] The above-mentioned variable incident angle ATR accessory has a top cover diameter of 26mm and a height of 5mm. It is made of aluminum alloy and has a sample hole with a diameter of 1.8mm in the center. The hemispherical ATR crystal made of zinc selenide is fixed in the circular groove in the center of the upper support by M4 screws, and an M4 gasket is placed in the middle to avoid damaging the ATR crystal.

[0010] The upper supporting part is 85mm long, 80mm wide and 5.66mm high. There is a 5mm hollow square supporting part on the lower end face, which plays a supporting role without blocking the light path. It is made of aluminum alloy. There is a circular groove in the center of the upper end face for accommodating the hemispherical ATR crystal.

[0011] The concave mirror part is 50mm long, 36mm wide and 18mm high. There is a square boss with a width of 10mm and a length of 18mm on the side. There is a round hole with a diameter of 9.5mm on it for fixing the fine-pitch screw. By turning the fine-pitch screw with a stroke of 6mm and fixing the screw with the M4 screw above, the left and right spacing between the concave mirror and the lower support can be achieved.

[0012] The lower receiving part is 50mm long, 36mm wide and 67mm high. A 6mm wide and 36mm long part is removed from one side of the upper end face for movement and adjustment with a fine-pitch screw. There is a 15mm wide and 60mm long square boss on the side of the lower end, with a 9.5mm diameter round hole on it for fixing the fine-pitch screw. The square through hole with a side length of 5mm is equipped with an M2 screw for fixing the spring. By turning the fine-pitch screw with a stroke of 6mm, the left and right spacing between the concave mirror and the lower receiving part can be achieved. The spring connected to the lower convex mirror can ensure the tightness of the two components during the adjustment process. The convex mirror part is 50mm long, 36mm wide and 67mm high. There is a 5mm square deep hole on the front side, which is equipped with an M2 screw for connecting and fixing the spring.

[0013] The base is 50mm long, 36mm wide and 20mm high, with four evenly distributed through holes with a diameter of 10mm for installing fine-pitch screws with a stroke of 6mm. The screw mounting holes are tightened and fixed on the side by M4 screws, which can adjust the upper and lower positions of the convex mirror and allow the light source to fall accurately at the appropriate position of the convex mirror.

[0014] The rotating mirror frame part has a diameter of 42mm and a thickness of 12.5mm. It is fixed to the lower supporting side by M2 screws and is used to rotate the shielding piece to adjust the attenuated total reflection incident angle. The hollow part has a diameter of 26mm.

[0015] The shielding piece has a diameter of 25.8 mm and a thickness of 2 mm, and is used to partially shield the optical path. In the rotating frame where the shielding lens is installed, the frame can rotate 360°, for example, the incident angle range is 31.48° to 36.75° at 0°, 32.93° to 39.45° at 120°, and 37.85° to 43.46° at 240°.

[0016] When the variable incident angle ATR accessory of the present invention is used to perform multi-depth infrared detection on the sample, the operation steps can be carried out as follows: first, the accessory is placed in the sample compartment of the spectrometer, and the positions of the various parts of the accessory are adjusted by fine-pitch screws until the spectrometer displays a higher transmittance. The sample is dripped onto the center of the hemispherical ATR crystal through the center of the upper cover and the gasket. The infrared beam emitted by the spectrometer enters the accessory after passing through a partially blocked rotating mirror frame, passes through a collimating mirror and a focusing mirror, and is incident on the sample to be tested at a certain angle in the hemispherical lens. After carrying the sample, it is returned to the detector in the spectrometer through a collimating mirror and a focusing mirror, and the sample spectrum under this incident angle can be obtained on the computer display screen of the spectrometer. By rotating the mirror frame to adjust the part of the light path blocked by the shading sheet, the attenuated total reflection angle can be changed, thereby obtaining the spectrum of the sample at different depths, and realizing the low cost, high precision, and simplification of the variable incident angle ATR accessory. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the variable incident angle ATR accessory provided by the present invention.

[0018] Figure 2 It is a device structure diagram of the infrared light path light passing part provided by the present invention.

[0019] Figure 3 It is a structural diagram of a rotating mirror frame portion provided by the present invention and equipped with a shielding lens.

[0020] Figure 4 The diagram is a light path diagram of the variable incident angle ATR accessory provided by the present invention installed in a spectrometer.

[0021] Description of Figure Numbers.

[0022] 1. Upper cover.

[0023] 2. Gasket.

[0024] 3. Hemispherical ATR crystal.

[0025] 4. Continue from above.

[0026] 5. M4 screws.

[0027] 6. Concave mirror.

[0028] 7. Fine pitch screw (stroke 13mm).

[0029] 8. Continue from next step.

[0030] 9. M2 screws.

[0031] 10. Spring.

[0032] 11. Convex mirror.

[0033] 12. Base.

[0034] 13. Fine pitch screw (stroke 6mm).

[0035] 14. Shade sheet (blocks 3 / 4).

[0036] 15. Rotating mirror frame.

[0037] 16. Spectrometer.

[0038] 17. Sample warehouse.

[0039] 18. Computer. DETAILED DESCRIPTION

[0040] In order to explain the technical content, structural features, ultimate purpose and presentation effect of the technical solution in detail, the following is a detailed description with reference to the specific drawings. Figures 1 to 4The invention provides a variable incident angle ATR accessory, comprising an upper cover (1), a hemispherical ATR crystal (3), an upper support (4), a concave mirror (6), a lower support (8), a convex mirror (11), and a base (12). The relative position of the concave mirror and the convex mirror is adjusted by a fine-pitch screw (7), and the relative height of the convex mirror and the base is adjusted by a fine-pitch screw (13). The hemispherical ATR crystal (3) is placed in the central groove of the upper support (4) and fixed by the upper cover (1) and the gasket (2).

[0041] Specifically, in the above embodiment, the rotating mirror frame (15) equipped with the light shielding sheet (14) is installed on the side of the lower support (8) by screws, such as Figure 3 The angle range of the attenuated total reflection incident angle can be adjusted by rotating the angle of the light shielding plate (14).

[0042] Specifically, in the above embodiment, Figure 4 The infrared light emitted by the spectrometer (16) passes through the rotating mirror frame (15) equipped with the shading plate (14), and then is collimated by the convex mirror (11). The collimated parallel light is focused by the concave mirror (6) and irradiated on the hemispherical ATR crystal (3) on which the sample is placed within a certain range of incident angles. After carrying the sample information, it is collimated and expanded by the concave mirror (6) and the convex mirror (11) in turn, and then returns to the detector part of the spectrometer (16). The above ATR accessories are all placed in the sample compartment (17) of the spectrometer (16), and the spectrum can be observed and recorded by a computer (18) connected to the spectrometer.

[0043] Specifically, in the above embodiment, Figure 4 The infrared light emitted by the spectrometer (16) passes through the rotating mirror frame (15) equipped with the shading plate (14), and then is collimated by the convex mirror (11). The collimated parallel light is focused by the concave mirror (6) and irradiated on the hemispherical ATR crystal (3) on which the sample is placed within a certain range of incident angles. After carrying the sample information, it is collimated and expanded by the concave mirror (6) and the convex mirror (11) in turn, and then returns to the detector part of the spectrometer (16). The above ATR accessories are all placed in the sample compartment (17) of the spectrometer (16), and the spectrum can be observed and recorded by a computer (18) connected to the spectrometer.

[0044] When using the variable incident angle ATR accessory of the present invention to perform multi-depth infrared detection on a sample, the following steps can be followed. The flow chart is as follows: Figure 4 As shown:

[0045] First, place the accessory in the sample compartment of the spectrometer, and adjust the position of each part of the accessory by fine-thread screws until the spectrometer displays a higher transmittance. Drop the sample through the center of the upper cover and the gasket to the center of the hemispherical ATR crystal. The infrared beam emitted by the spectrometer enters the accessory after passing through the partially blocked rotating mirror frame, passes through the collimator and focusing lens, and is incident on the sample to be tested at a certain angle in the hemispherical lens. After carrying the sample, it passes through the collimator and focusing lens back to the detector in the spectrometer, and the sample spectrum under this incident angle can be obtained on the computer display of the spectrometer. By rotating the mirror frame to adjust the part of the light path blocked by the shading sheet, the attenuated total reflection angle can be changed, thereby obtaining the spectrum of the sample at different depths, realizing the low cost, high precision and simplicity of the variable incident angle ATR accessory.

[0046] The patent of this invention relates to a variable incident angle ATR accessory. Since different samples have different refractive indices, the attenuated total reflection incident depths are also different. The environmental conditions during use, such as different water vapor and carbon dioxide concentrations, will also affect the obtained spectra. The optimal parameters required for attenuated total reflection of different samples at different incident angles are set to ensure that the attenuated total reflection can occur normally. Experiments are carried out and the spectra measured in the experiments can be used to analyze the chemical bonds, strength, and other characteristics of the test samples.

[0047] Although the above embodiments have been described, once those skilled in the art know the basic creative concepts, they can make additional changes and modifications to these embodiments. Therefore, the above description is only an embodiment of the present invention and does not limit the patent protection scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the specification and drawings of the present invention, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A variable incident angle ATR accessory comprises, from top to bottom, an upper cover, a gasket, a hemispherical ATR crystal, an upper connection, a concave mirror, a lower connection, a rotating mirror frame equipped with a light shielding sheet, a spring, a convex mirror, and a base. The rotating mirror frame equipped with a shielding lens is connected to the light entrance window end of the lower connection of the accessory, facing the incident light source of the spectrometer, and the light exit window end of the lower connection of the accessory faces the detection window of the spectrometer. The lower part of the lower connection is connected to the convex mirror, the lower part of the convex mirror is connected to the base, the upper part of the lower connection is connected to the concave mirror, the upper part of the concave mirror is connected to the upper connection, the upper connection carries the hemispherical ATR crystal, and the upper part is fixed by the upper cover and the gasket.

2. A variable incident angle ATR accessory according to claim 1, characterized in that The variable incident angle, the upper cover has a diameter of 26mm, a height of 5mm, and is made of aluminum alloy. There is a sample hole with a diameter of 1.8mm in the center. The hemispherical ATR crystal made of zinc selenide is fixed in the circular groove in the center of the upper connection by M4 screws, and an m4 gasket is placed in the middle to avoid damaging the ATR crystal. The upper connection part is 85mm long, 80mm wide, and 5.66mm high. The lower end face has a 5mm hollow square connection, which plays a supporting role without blocking the light path. The material is aluminum alloy, and there is a circular groove in the center of the upper end face for placing the hemispherical ATR crystal. The concave mirror part is 50mm long, 36mm wide, and 18mm high. There is a square boss with a width of 10mm and a length of 18mm on the side, and there is a circular hole with a diameter of 9.5mm on it, which is used to fix the fine-pitch screw. By rotating the fine-pitch screw with a stroke of 6mm, the screw is fixed by the M4 screw above, and the left and right spacing between the concave mirror and the lower connection below can be achieved. The lower receiving part is 50mm long, 36mm wide and 67mm high. A 6mm wide and 36mm long part is removed from one side of the upper end face for movement and adjustment with a fine-pitch screw. There is a 15mm wide and 60mm long square boss on the side of the lower end, with a 9.5mm diameter round hole on it for fixing the fine-pitch screw. The square through hole with a side length of 5mm is equipped with an M2 screw for fixing the spring. By turning the fine-pitch screw with a stroke of 6mm, the left and right spacing between the concave mirror and the lower receiving part can be achieved. The spring connected to the lower convex mirror can ensure the tightness of the two components during the adjustment process. The convex mirror part is 50mm long, 36mm wide and 67mm high. There is a 5mm square deep hole on the front side, which is equipped with an M2 screw for connecting and fixing the spring. The base is 50mm long, 36mm wide, and 20mm high, with four evenly distributed through holes of 10mm in diameter for installing fine-thread screws with a stroke of 6mm. The screw mounting holes are tightened and fixed on the side by M4 screws, which can adjust the upper and lower positions of the convex mirror so that the light source can fall accurately on the appropriate position of the convex mirror. The rotating mirror frame has a diameter of 42mm and a thickness of 12.5mm. It is fixed to the lower supporting side by M2 screws and is used to rotate the shielding plate to adjust the incident angle of attenuated total reflection. The hollow part has a diameter of 26mm. The shielding plate has a diameter of 25.8mm and a thickness of 2mm, and is used to partially block the light path.

3. The variable incident angle ATR accessory for an infrared spectrometer according to claim 1, characterized in that: The accessory base is equipped with a fine-pitch screw with a stroke of 6mm, which is used to support and adjust the height of the convex mirror; the lower support and the convex mirror are connected to the spring through a fine-pitch screw with a stroke of 13mm, and the fine-pitch screw is used to adjust the front-to-back distance between the lower support and the concave mirror. Two springs with a stroke of 15.5mm are used to ensure parallel movement; the lower support and the concave mirror are connected through two fine-pitch screws with a stroke of 13mm, which are used to adjust the left-right distance between the concave mirror and the lower support. Through the above screws, the up-and-down position adjustment of the accessory relative to the optical path and the front-to-back, left-to-right, left-to-right position adjustment between the concave mirror and the convex mirror can be achieved.

4. The variable incident angle ATR accessory for an infrared spectrometer according to claim 1, characterized in that: The center of the accessory upper cover has a sample through hole with a diameter of 1.8 mm, which is installed on the upper part of the ATR crystal through an m4 gasket. The sample is dripped onto the zinc selenide hemisphere through the sample hole in the upper cover, and the attenuated total reflection optical path focuses the infrared light on the 1.8mm sample area.

5. The variable incident angle ATR accessory for an infrared spectrometer according to claim 1, characterized in that: The accessory uses a partially blocked rotating mirror frame in the incident light area, and realizes a certain range of incident angle adjustment by rotating and blocking part of the light path, thereby changing the depth of the detected sample.

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