A compensation method for abnormal measurement laser pulse in Fourier transform infrared spectrometer

Abstract

The present invention provides a method for compensating for abnormal metrological laser pulses in a Fourier transform infrared spectrometer, relating to the technical field of Fourier transform infrared spectrometers. The method comprises a control module, a time window calculation module, a timer module, and an ADC trigger pulse generation module; the control module is used to control the operation of the entire scheme; the time window calculation module is used to calculate the effective time window, and its calculation logic is as follows: S1: After reset, the default effective time window is set based on the moving mirror stabilization speed + fluctuation. This scheme ultimately enables direct detection of missing metrological laser pulses at the hardware circuit stage, ensuring consistent interference pattern data length, eliminating the need for subsequent compensation through complex data processing. This method can detect both missing metrological laser pulses and excess metrological laser pulses caused by interference.

Description

Technical Field

[0001] The present invention relates to the technical field of Fourier infrared spectrometers, and in particular to a method for compensating for abnormal measurement laser pulses in a Fourier infrared spectrometer. Background Art

[0002] As a crucial instrument in modern analytical chemistry, the Fourier transform infrared spectrometer (FTIR) is widely used in numerous fields, including scientific research, industrial production, and quality control. With the continuous advancement of technology, the performance of FTIR continues to improve, moving towards higher resolution, faster scanning speeds, and greater sensitivity to meet increasingly complex analytical needs. However, its complex internal optical and electronic systems also face new challenges. Even the slightest anomaly in any link can affect the accuracy of measurement results.

[0003] The Fourier transform infrared spectrometer uses a metering laser to trigger the equal-path difference ADC sampling of the infrared signal. This is mainly because the wavelength and frequency of the metering laser are single and stable, and can be used as a scale for measuring the interference signal of mid- and far-infrared light (wavelength 2.5um-25um).

[0004] For example, the commonly used HeNe laser has a common wavelength of 632.8nm, which changes very little when the temperature and air pressure environmental parameters change. The interference signal waveform after passing through the interferometer is close to a sine wave. By generating pulses at the moment when the amplitude of the interference signal is close to 0V (also called the "zero point"), an equal optical path difference trigger pulse can be obtained. The optical path difference between the moving mirror and the fixed mirror of the interferometer corresponding to each pulse interval is half the HeNe wavelength, that is, 632.8nm / 2=316.4nm.

[0005] Because the interferometer's optical path difference changes simultaneously and equally on both infrared and HeNe light, each HeNe zero-crossing pulse corresponds to a 316.4nm change in the infrared optical path difference. Even if the zero-crossing pulses aren't perfectly spaced due to uneven mirror motion, using HeNe zero-crossing pulses to trigger infrared interferometer signal sampling ensures that the infrared interferometer signal is sampled every 316.4nm of optical path difference, ensuring the accuracy of equal optical path difference sampling. Therefore, HeNe light is called a measuring scale. Frequency-stabilized lasers of other wavelengths can also serve as metrological lasers, as long as the frequency and wavelength are stable.

[0006] Since the total optical path difference L of an infrared interferogram is roughly inversely proportional to the spectral resolution R, it is generally necessary to achieve a 1cm -A spectral resolution of 1 is required to analyze organic compounds with complex structures and dense functional group absorption peaks. This resolution corresponds to a total optical path difference of 1 cm. Calculated based on a single-sampling optical path difference of 316.4 nm (the metrological laser is a HeNe laser), an interferogram requires 31,606 sampling points and an equal number of metrological laser pulses. In addition, in some application scenarios, to improve the signal-to-noise ratio, multiple interferograms are accumulated and averaged to obtain an interferogram with a higher signal-to-noise ratio. This requires more metrological laser pulses as sampling points for the ADC.

[0007] However, in factory workshops, vehicles, satellites and other application scenarios, strong electromagnetic interference or high-energy radiation may cause occasional errors in the metrology laser pulse generation circuit, resulting in a few more or fewer pulses in the more than 30,000 metrology laser trigger pulses required for an interference pattern. This will cause the length of each interference pattern sequence to be inconsistent and unable to be correctly aligned and averaged. In addition, for a single interference pattern, the extra erroneous trigger pulses will cause the interference to be Figure 1 Oversampling of a very small area of ​​the segment, the missing trigger pulse will cause interference Figure 1 The undersampling of a very small area in the segment, and the subsequent FFT will convert the interference pattern into a spectrum by default according to the correct sampling method of equal optical path difference, resulting in distortion of the generated spectrum, spectral line position offset, spectral line intensity imbalance, etc., affecting usage.

[0008] Existing paper: Dutil Y, Lantagne S, Dubé S, et al. ACE-FTS Level 0 To 1 Data Processing [C]. Proceedings of SPIE. 2002, 4814:102-110. (Journal); This paper's scheme assumes that the lost metering pulse occurs in the smaller-amplitude edge of the interferogram, where the final spectrum is less affected (the larger-amplitude central region has a greater impact on the final spectrum, but this central region accounts for less than 1 / 10 of the total interferogram sequence). If an unknown number of h metering laser pulses is lost, the central maximum of the interferogram will shift by h data points, offsetting the x-axis zero by h positions. This shift, after performing an FFT, will introduce a linear phase error in the spectrum that is related to h. Simply obtaining the magnitude of h can determine this magnitude. By shifting the interferogram back by h positions and performing the FFT again, the spectral distortion introduced by the lost metering pulse can be largely eliminated.

[0009] In the paper, by calculating the measured complex spectrum with the confirmed cold reference complex spectrum and hot reference complex spectrum, the linear phase error value can be obtained, and the size of h can be determined. Then, the interference pattern is translated back as a whole, and the central area of ​​the interference pattern is aligned to the zero point of the x-axis and then FFT is performed, which can eliminate the spectral distortion problem caused by the loss of the metering pulse to a certain extent.

[0010] This technology performs remedial data processing on the interferogram data where the metering laser pulse has been lost. The number of lost pulses is found, and the interferogram is then shifted by the same number of positions to return the center of the interferogram to the zero point of the x-axis. This can eliminate the spectral distortion caused by the loss of metering pulses to a certain extent. However, this technology has the following problems:

[0011] 1. The loss of metering laser pulses cannot be directly detected at the hardware circuit stage, but must be remedied after the acquisition is completed;

[0012] 2. It can only handle the scenario where several metering laser pulses are lost, but cannot solve the situation where extra metering laser pulses are caused by interference;

[0013] 3. The only way to remedy the loss of metering pulses is to identify the number of missing data points in the interferogram's edge with small amplitudes and translate the interferogram back to the zero point of the x-axis. The loss of a few small amplitude data points will not have a significant impact on the overall spectrum. However, if the metering pulse is lost in the center of the interferogram with a large amplitude, the spectrum will be severely distorted and a large amount of information will be lost. This problem cannot be fixed by translating back to the zero point of the x-axis, and the interferogram will have to be discarded as a whole, resulting in data loss.

[0014] 4. When multiple interferogram data need to be accumulated and averaged, this solution only translates the center area of ​​the interferogram back to the x-axis zero point, which can only ensure the alignment of the area near the x-axis zero point. The edge area will still be misaligned, and the data misalignment during the accumulated averaging will introduce new problems.

[0015] 5. The interference pattern amplitude values ​​corresponding to the position where the metering laser pulse was lost cannot be inferred and recovered; these values ​​are completely lost.

[0016] Therefore, it is necessary to provide a compensation method for the abnormal measurement laser pulse in a Fourier transform infrared spectrometer to solve the above technical problems. Summary of the Invention

[0017] The present invention provides a compensation method for abnormal measurement laser pulses in a Fourier transform infrared spectrometer, which solves the technical problem in the related art that it is inconvenient to detect laser pulse loss and compensate immediately during the acquisition process.

[0018] In order to solve the above technical problems, the present invention provides a compensation method for abnormal measurement laser pulse in a Fourier transform infrared spectrometer, which includes a control module, a time window calculation module, a timer module and an ADC trigger pulse generation module;

[0019] The control module is used to control the operation process of the entire solution;

[0020] The time window calculation module is used to calculate the effective time window, and its calculation logic is as follows:

[0021] S1: After reset, the default effective time window is set according to the moving mirror stabilization speed + fluctuation;

[0022] The designed measuring laser pulse wavelength is λnm, and the target optical path difference change speed caused by the moving mirror is vcm / s. According to the two zero-crossing pulses generated by each measuring laser wavelength, the ideal time interval of the measuring laser pulse is:

[0023]

[0024] The actual moving mirror will not produce an optical path difference at the ideal vcm / s speed due to reasons such as the drive circuit and mechanical vibration. Generally, it is required to be controlled within 2%.

[0025] Leave a certain margin and set the time window of the metering pulse according to 2 times, that is, ±4%. The time window is set to:

[0026]

[0027] A HeNe laser with a wavelength of 632.8 nm is used as the metering laser. Based on the ideal optical path difference of 1 cm / s, the time window of the metering pulse is set at ±4%, that is, 30.3 µs to 32.9 µs. If the next metering pulse arrives within this time range, it is considered a valid pulse.

[0028] S2: For the "missing pulse situation", since the supplementary generated pulse has exceeded the valid time window, the next valid time window should be set closer;

[0029] However, in order to facilitate unified processing, the effective time window remains unchanged, but the advance amount of half a time window is increased to the "timer module", that is, the starting point of the next timer module is set to

[0030] The timer module is used to calculate the effective time window, and its operating logic is as follows:

[0031] S1: After receiving the "start" command from the control module, the timing starts from the preset timing starting point. When running at a main frequency of 100MHz, the timing accuracy reaches 10ns;

[0032] S2: After receiving the "reset / clear" command from the control module, the timer module stops timing and the duration is cleared;

[0033] S3: After receiving the "add advance" command from the control module, the corresponding advance is added to the starting point of the timer module. This function will be used in the case of "missing pulse";

[0034] The ADC trigger pulse generation module is used to generate a trigger signal that ultimately drives the ADC to collect infrared interferograms. Its operating logic is as follows:

[0035] S1: The control module determines that the current original pulse is within the "valid time window", and this module outputs an ADC trigger pulse;

[0036] S2: The control module determines that the current original pulse is earlier than the "valid time window", and this module discards the original pulse and does not generate an ADC trigger pulse;

[0037] S3: If the control module determines that no new pulse arrives at the end of the “valid time window”, this module generates another pulse and outputs it as an ADC trigger pulse.

[0038] Preferably, the Fourier transform infrared spectrometer is mainly composed of an infrared light source, a metrological laser, an interferometer, a sample to be measured, a metrological laser pulse generating circuit, an infrared signal ADC acquisition circuit, and a computer.

[0039] Preferably, compared with the traditional Fourier infrared spectroscopy structure, the newly added control module, time window calculation module, timer module and ADC trigger pulse generation module are used to intercept and reprocess the original pulses generated by the metering laser pulse generation circuit, and the pulses that are confirmed to be free of abnormalities after processing are then used for infrared signal ADC acquisition.

[0040] Preferably, the spectrometer improved based on the compensation method for the abnormal measurement laser pulse in the Fourier transform infrared spectrometer requires the use of a processing box, a linear motion mechanism and an extrusion mechanism when testing powder samples;

[0041] The linear motion mechanism includes two sliding brackets fixedly mounted on the bottom of the inner wall of the processing box, and a moving seat is slidably connected to the opposite side of the two sliding brackets. The inner side of the moving seat is threadedly connected to a threaded screw, and the front end of the threaded screw is rotatably connected to the front side of the inner wall of the processing box. A driving motor for driving the threaded screw to rotate is provided on the front side of the processing box;

[0042] The extrusion mechanism includes two guide rods fixedly arranged on the inner side of the top of the processing box, the surfaces of the two guide rods are slidably connected to movable plates, the surfaces of the tops of the two movable plates are slidably connected to the inner side of the processing box, the inner sides of the two movable plates are slidably connected to extrusion rods, the opposite ends of the two extrusion rods and the opposite sides of the two movable plates are fixed with extrusion blocks, the surfaces of the two extrusion rods and the sides of the two movable plates separated are sleeved with springs, the separated ends of the two extrusion rods are fixed with rotating frames, the inner sides of the two rotating frames are rotatably connected to rotating wheels, and trapezoidal plates are fixed on both sides of the inner wall of the processing box.

[0043] Preferably, two clamping frames are fixed on the top of the movable seat, two card blocks are fixed on opposite sides of the two clamping frames, sample clamps are provided on opposite sides of the two clamping frames, the surfaces of the sample clamps are slidably connected to the surfaces of the card blocks, and the spectrometer body is fixed on the back of the processing box.

[0044] Preferably, a slide groove is provided on the inner side of the top of the processing box for use with the two movable plates to allow the two movable plates to slide back and forth. The surfaces of the two extrusion rods are provided with grooves for sliding horizontally on the inner side of the movable plate. The surfaces of the two rotating wheels are respectively fitted with the surfaces of the two trapezoidal plates.

[0045] Preferably, the two extrusion blocks are cylinders, a circular through hole for use with the two extrusion blocks is opened on the inner side of the sample clamp, a cylindrical through hole is opened vertically on the inner side of the sample clamp, and the cylindrical through hole is connected to the circular through hole.

[0046] Preferably, a pressure display mechanism is fixedly provided on the left side of the bottom of the inner wall of the processing box, and the pressure display mechanism includes a rotating bracket fixedly provided on the left side of the bottom of the inner wall of the processing box, and the inner side of the rotating bracket is horizontally rotatably connected with a rotating shaft, and the right end of the rotating shaft is fixedly provided with a gear, and the left side of the top of the movable seat is fixedly provided with a gear plate, and the gear is engaged with the gear plate. A display dial is fixedly provided on the left side of the processing box, and a pointer is provided inside the display dial. The left end of the rotating shaft is fixedly connected to the right side of the pointer.

[0047] Preferably, an adjustment mechanism is fixed on one side of the two sliding brackets, and the adjustment mechanism includes a mounting block fixed on one side of the two sliding brackets, the inner sides of the two mounting blocks are threadedly connected with screws, the front ends of the two screws are fixed with limit columns, and the rear ends of the two screws are fixed with knobs.

[0048] Preferably, the top of the processing box is connected to a conical hopper, the top of the conical hopper is provided with a cover plate, and the bottoms of the processing box and the spectrometer body are both fixed with two supporting blocks.

[0049] Compared with related technologies, the compensation method for abnormal measurement laser pulses in a Fourier transform infrared spectrometer provided by the present invention has the following beneficial effects:

[0050] This method directly detects the loss of metering laser pulses at the hardware circuit stage to ensure that the length of the interference pattern data is consistent, and there is no need to make up for it through subsequent complex data processing methods. It can detect the loss of metering laser pulses as well as the extra metering laser pulses caused by interference; no matter whether the loss or increase of metering laser pulses occurs in a small-amplitude area at the edge of the interference pattern or in a large-amplitude area in the center of the interference pattern, the problem pulses can be supplemented or discarded, and the entire interference pattern does not need to be discarded; by identifying the metering laser pulse problem at the hardware stage and supplementing or discarding the pulse, it can be ensured that the interference pattern data length is consistent and will not be too long or too short, and the accumulation of multiple interference patterns can ensure that each point can be aligned and not misaligned; by identifying the metering laser pulse problem at the hardware stage and supplementing or discarding the pulse, even if the pulse time introduces a time delay deviation of the order of microseconds (us) due to the set time window problem, it can be guaranteed that the infrared interference pattern at that point has a value that is close to the true value. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0052] Figure 1 A diagram showing a method for measuring laser pulse occurrence time provided by the present invention;

[0053] Figure 2 A flow chart of the metrology laser pulse compensation and repair provided by the present invention;

[0054] Figure 3 The control module operation flow chart provided by the present invention;

[0055] Figure 4 The best structural diagram provided by the present invention;

[0056] Figure 5 A schematic structural diagram of a bottom view of a processing box provided by the present invention;

[0057] Figure 6 A schematic structural diagram of a cross-sectional view of a processing box provided by the present invention;

[0058] Figure 7 A schematic structural diagram of the linear motion mechanism provided by the present invention;

[0059] Figure 8 for Figure 7 A schematic structural diagram of the clamping frame shown;

[0060] Figure 9A schematic structural diagram of the extrusion mechanism provided by the present invention;

[0061] Figure 10 for Figure 6 The threaded screw shown drives the movable seat and the sample holder to move forward, and the movable plate drives the extrusion rods, the rotating frame and the rotating wheel to move forward. The trapezoidal plate acts to drive the two extrusion rods to drive the two extrusion blocks to move to opposite sides.

[0062] Figure 11 A schematic structural diagram of the pressure display mechanism provided by the present invention;

[0063] Figure 12 A schematic diagram of a state in which the threaded screw provided by the present invention drives the movable seat and the gear plate to move forward, causing the gear to drive the pointer to rotate counterclockwise via the rotating shaft;

[0064] Figure 13 This is a structural schematic diagram of the adjustment mechanism provided by the present invention.

[0065] Description of Figure Numbers:

[0066] 1. Processing box;

[0067] 2. Linear motion mechanism; 21. Sliding bracket; 22. Moving seat; 23. Screw rod; 24. Driving motor;

[0068] 3. Extrusion mechanism; 31. Guide rod; 32. Moving plate; 33. Extrusion rod; 34. Extrusion block; 35. Spring; 36. Rotating frame; 37. Rotating wheel; 38. Trapezoidal plate;

[0069] 4. Clamping frame; 5. Clamping block; 6. Sample clamp; 7. Spectrometer body;

[0070] 8. Pressure display mechanism; 81. Rotating bracket; 82. Rotating shaft; 83. Gear; 84. Gear plate; 85. Display dial; 86. Pointer;

[0071] 9. Adjustment mechanism; 91. Mounting block; 92. Screw; 93. Limiting column; 94. Knob;

[0072] 10. Conical bucket; 11. Cover plate; 12. Support block.

[0073] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0074] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0075] The invention provides a compensation method for abnormal measurement laser pulse in a Fourier transform infrared spectrometer.

[0076] First embodiment:

[0077] See also Figures 1 to 3 ,A compensation method for the abnormal measurement laser pulse in a Fourier infrared spectrometer, comprising a control module, a time window calculation module, a timer module, and an ADC trigger pulse generation module;

[0078] The control module is used to control the operation process of the entire solution;

[0079] The time window calculation module is used to calculate the effective time window, and its calculation logic is as follows:

[0080] S1: After reset, the default effective time window is set according to the moving mirror stabilization speed + fluctuation;

[0081] The designed measuring laser pulse wavelength is λnm, and the target optical path difference change speed caused by the moving mirror is vcm / s. According to the two zero-crossing pulses generated by each measuring laser wavelength, the ideal time interval of the measuring laser pulse is:

[0082]

[0083] The actual moving mirror will not produce an optical path difference at the ideal vcm / s speed due to reasons such as the drive circuit and mechanical vibration. Generally, it is required to be controlled within 2%.

[0084] Leave a certain margin and set the time window of the metering pulse according to 2 times, that is, ±4%. The time window is set to:

[0085]

[0086] A HeNe laser with a wavelength of 632.8 nm is used as the metering laser. Based on the ideal optical path difference of 1 cm / s, the time window of the metering pulse is set at ±4%, that is, 30.3 µs to 32.9 µs. If the next metering pulse arrives within this time range, it is considered a valid pulse.

[0087] S2: For the "missing pulse situation", since the supplementary generated pulse has exceeded the valid time window, the next valid time window should be set closer;

[0088] However, in order to facilitate unified processing, the effective time window remains unchanged, but the advance amount of half a time window is increased to the "timer module", that is, the starting point of the next timer module is set to

[0089] The timer module is used to calculate the effective time window, and its operating logic is as follows:

[0090] S1: After receiving the "start" command from the control module, the timing starts from the preset timing starting point. When running at a main frequency of 100MHz, the timing accuracy reaches 10ns;

[0091] S2: After receiving the "reset / clear" command from the control module, the timer module stops timing and the duration is cleared;

[0092] S3: After receiving the "add advance" command from the control module, the corresponding advance is added to the starting point of the timer module. This function will be used in the case of "missing pulse";

[0093] The ADC trigger pulse generation module is used to generate a trigger signal that ultimately drives the ADC to collect infrared interferograms. Its operating logic is as follows:

[0094] S1: The control module determines that the current original pulse is within the "valid time window", and this module outputs an ADC trigger pulse;

[0095] S2: The control module determines that the current original pulse is earlier than the "valid time window", and this module discards the original pulse and does not generate an ADC trigger pulse;

[0096] S3: If the control module determines that no new pulse arrives at the end of the “valid time window”, this module generates another pulse and outputs it as an ADC trigger pulse.

[0097] The Fourier infrared spectrometer is mainly composed of an infrared light source, a measuring laser, an interferometer, a sample to be measured, a measuring laser pulse generating circuit, an infrared signal ADC acquisition circuit, and a computer;

[0098] Preferably, the interferometer interferes with the optical signals of the infrared light source and the metrological laser, and obtains an interference pattern containing all the frequency and intensity information of the light source and an interference pattern containing the frequency and intensity information of the metrological laser light source;

[0099] After that, the metering laser pulse generation circuit is responsible for converting the metering laser interferogram into equal optical path difference ADC acquisition trigger pulses, triggering the infrared signal ADC acquisition circuit to perform equal optical path difference sampling on the infrared light interferogram;

[0100] The computer receives the infrared interference pattern collected by the ADC and performs a fast Fourier transform (FFT) on the interference pattern to calculate the infrared spectrum. The spectrum can reflect the distribution of the intensity of the light signal after the infrared light source passes through the sample with frequency as the horizontal axis. The chemical composition of the sample is analyzed based on the difference between the spectrum of the infrared light source itself and the spectrum after passing through the sample.

[0101] Compared with the traditional Fourier infrared spectroscopy structure, the newly added control module, time window calculation module, timer module and ADC trigger pulse generation module are used to intercept and reprocess the original pulses generated by the metering laser pulse generation circuit. After processing, the pulses that are confirmed to be free of abnormalities are then used for infrared signal ADC acquisition.

[0102] In this embodiment, compared with the existing solution that uses data processing methods to identify the number of lost pulses and perform a certain degree of remediation after an anomaly has occurred, a control module, a time window calculation module, a timer module, and an ADC trigger pulse generation module are newly added to monitor the metering laser pulses in real time from the hardware stage. While maintaining the fluctuation of the moving mirror motion speed within a certain error (generally 2%), an FPGA or other processor is used to monitor the time interval between adjacent metering laser pulses in real time and predict the time window for the next metering laser pulse to appear. When a newly generated metering pulse is found to appear ahead of the time window, it is considered to be an extra metering pulse caused by interference and is discarded. The ADC is not triggered to collect the infrared interferogram. When it is found that the time window has expired and a new metering pulse has not been generated, a metering pulse is automatically added within the processor and the ADC is triggered to collect the infrared interferogram. This facilitates the detection of laser pulse loss during the collection process and immediate compensation.

[0103] Second embodiment:

[0104] See also Figures 4 to 10 , the spectrometer improved based on the compensation method of the measurement laser pulse anomaly in the Fourier transform infrared spectrometer, when testing powder samples, needs to use the processing box 1, the linear moving mechanism 2 and the extrusion mechanism 3;

[0105] The linear motion mechanism 2 includes two sliding brackets 21 fixed to the bottom of the inner wall of the processing box 1, and a moving seat 22 is slidably connected to the opposite side of the two sliding brackets 21. The inner side of the moving seat 22 is threadedly connected to a threaded screw 23. The front end of the threaded screw 23 is rotatably connected to the front side of the inner wall of the processing box 1. A driving motor 24 for driving the threaded screw 23 to rotate is provided on the front side of the processing box 1.

[0106] Please combine Figure 6 and Figure 7 : Start the drive motor 24, and the drive motor 24 rotates to drive the threaded screw 23 to rotate. The threaded screw 23 rotates and drives the movable base 22 to slide forward on the inner side of the two sliding brackets 21. The moving direction of the movable base 22 can be adjusted by the forward and reverse rotation of the drive motor 24;

[0107] Preferably, the inner side of the movable seat 22 is provided with a threaded groove for use with the threaded screw 23. The rotation of the threaded screw 23 can drive the movable seat 22 to move forward and backward. The surface of the movable seat 22 is provided with grooves for use with the two sliding brackets 21.

[0108] The squeezing mechanism 3 includes two guide rods 31 fixedly arranged on the inner side of the top of the processing box 1, the surfaces of the two guide rods 31 are slidably connected to movable plates 32, the surfaces of the tops of the two movable plates 32 are slidably connected to the inner side of the processing box 1, the inner sides of the two movable plates 32 are slidably connected to squeezing rods 33, the opposite ends of the two squeezing rods 33 and the opposite sides of the two movable plates 32 are fixed with squeezing blocks 34, the surfaces of the two squeezing rods 33 and the sides of the two movable plates 32 are sleeved with springs 35, the separated ends of the two squeezing rods 33 are fixed with rotating frames 36, the inner sides of the two rotating frames 36 are rotatably connected to rotating wheels 37, and trapezoidal plates 38 are fixed on both sides of the inner wall of the processing box 1;

[0109] Please combine Figure 9 and Figure 10 When the movable seat 22 drives the sample holder 6 to move forward, the movement of the sample holder 6 drives the two movable plates 32 to slide forward on the inner side of the processing box 1. During the movement, the two movable plates 32 drive the squeezing rods 33, the squeezing blocks 34, the rotating frame 36 and the rotating wheels 37 to move forward. Under the action of the two trapezoidal plates 38, the two rotating wheels 37 cause the two squeezing rods 33 to move to the opposite side during the movement, and cause the two springs 35 to contract. The movement of the two squeezing rods 33 to the opposite side drives the two squeezing blocks 34 to move to the opposite side. As the movable seat 22 gradually moves forward, the two squeezing blocks 34 are slowly inserted into the circular through holes in the sample holder 6.

[0110] Furthermore, when the movable base 22 drives the sample holder 6 to move backward, at this time, if the two squeezing blocks 34 are located in the circular through-holes in the sample holder 6, the movement of the sample holder 6 will drive the squeezing blocks 34, the squeezing rod 33, the rotating frame 36 and the rotating wheel 37 to move backward, and at the same time, the two movable plates 32 will slide backward on the inner side of the processing box 1. In the process of the movable base 22 driving the sample holder 6 to move backward gradually, the expansion of the spring 35 will cause the two squeezing blocks 34 to gradually disengage from the circular through-holes in the sample holder 6. After disengagement, the movable base 22 will drive the sample holder 6 to move backward alone.

[0111] Preferably, convex baffles are provided on both sides of the sample holder 6. When the sample holder 6 moves backward, the convex baffles drive the two movable plates 32 to move backward.

[0112] Two clamping frames 4 are fixedly provided on the top of the movable base 22, and two clamping blocks 5 are fixedly provided on opposite sides of the two clamping frames 4. Sample clamps 6 are provided on opposite sides of the two clamping frames 4, and the surfaces of the sample clamps 6 are slidably connected to the surfaces of the clamping blocks 5. A spectrometer body 7 is fixedly provided on the back of the processing box 1;

[0113] Preferably, a through slot is provided in the spectrometer body 7 for use with the processing box 1, and the rear ends of the two sliding brackets 21 are fixedly connected to the bottom of the inner wall of the spectrometer body 7. When the movable seat 22 drives the sample clamp 6 to move to the interior of the spectrometer body 7, the flip cover on the top of the spectrometer body 7 is opened, and then the sample clamp 6 is pulled out upward, so that the sample clamp 6 can be cleaned or replaced.

[0114] The inner side of the top of the processing box 1 is provided with a slide groove for use with the two movable plates 32, which is used to allow the two movable plates 32 to slide back and forth. The surfaces of the two extrusion rods 33 are provided with grooves for sliding horizontally on the inner side of the movable plates 32. The surfaces of the two rotating wheels 37 are respectively in contact with the surfaces of the two trapezoidal plates 38.

[0115] Preferably, the tops of the two movable plates 32 are both provided with raised blocks. When the two squeezing blocks 34 are separated from the circular through-holes in the sample clamp 6, the movable seat 22 alone drives the sample clamp 6 to move backward. At this time, if the top position of the movable plate 32 is not located at the last position of the inner slide groove at the top of the processing box 1, the top position of the movable plate 32 can be slid to the last position of the inner slide groove at the top of the processing box 1 by the raised blocks. After sliding to the specified position, when the sample clamp 6 moves forward and the raised baffle contacts the movable plate 32, the two squeezing blocks 34 are respectively located on both sides of the circular through-hole in the sample clamp 6, forming a blocking state for the circular through-hole.

[0116] The two extrusion blocks 34 are cylindrical, and a circular through hole is opened on the inner side of the sample clamp 6 for use with the two extrusion blocks 34. A cylindrical through hole is opened vertically on the inner side of the sample clamp 6, and the cylindrical through hole is connected to the circular through hole;

[0117] Preferably, the circular through hole is used to place powder samples, and the cylindrical through hole is used to put the powder samples into the circular through hole.

[0118] In this embodiment, compared with the existing method of independently tableting powder samples using a tablet press and then placing them into a Fourier transform infrared spectrometer for detection, the present invention adjusts the two squeezing blocks 34 to the two sides of the circular through hole in the sample holder 6 to form a blocking state for the circular through hole, and then the powdered sample is placed into the circular through hole through the cylindrical through hole. The sample holder 6 is driven forward by the movable seat 22. Under the action of the rotating wheel 37, the rotating frame 36, the squeezing rod 33, the spring 35 and the trapezoidal plate 38, the two squeezing blocks 34 are slowly inserted into the circular through hole in the sample holder 6, so that the powdered sample is squeezed into thin slices by the squeezing blocks 34. The sample holder 6 is driven backward by the movable seat 22, so that the squeezing blocks 34 are separated from the sample holder 6, so that the movable seat 22 alone drives the sample holder 6 and the sample into the spectrometer body 7 for detection. This greatly simplifies the steps of the spectrometer body 7 for detecting powdered samples, reduces the manual participation in the detection, and is suitable for batch detection of powdered samples.

[0119] Third embodiment:

[0120] See also Figures 11 to 13 , a pressure display mechanism 8 is fixedly provided on the left side of the bottom of the inner wall of the processing box 1, and the pressure display mechanism 8 includes a rotating bracket 81 fixedly provided on the left side of the bottom of the inner wall of the processing box 1, and the inner side of the rotating bracket 81 is horizontally rotatably connected to a rotating shaft 82, and the right end of the rotating shaft 82 is fixedly provided with a gear 83, and the left side of the top of the movable seat 22 is fixedly provided with a gear plate 84, and the gear 83 is meshed with the gear plate 84. A display dial 85 is fixedly provided on the left side of the processing box 1, and a pointer 86 is provided inside the display dial 85. The left end of the rotating shaft 82 is fixedly connected to the right side of the pointer 86;

[0121] Please combine Figure 11 and Figure 12 When the movable base 22 drives the sample holder 6 to move forward, the movement of the movable base 22 drives the gear plate 84 to move forward. The movement of the gear plate 84 drives the gear 83 to rotate counterclockwise. The gear 83 drives the pointer 86 to rotate counterclockwise through the rotating shaft 82. By observing the rotation position of the pointer 86 in the display dial 85, the degree of compression of the powder sample by the two squeezing blocks 34 can be seen.

[0122] Furthermore, when the movable seat 22 drives the sample holder 6 to move backward, it also drives the gear plate 84 to move backward. The gear plate 84 moves backward, which in turn drives the gear 83 to rotate clockwise. When the gear plate 84 separates from the gear 83, the pointer 86 rotates clockwise to the 0 degree position of the display dial 85.

[0123] Preferably, when the two squeezing blocks 34 are respectively located on both sides of the circular through hole in the sample holder 6 to form a blocking state for the circular through hole, the pointer 86 will rotate 45 degrees counterclockwise.

[0124] An adjustment mechanism 9 is fixedly provided on one side of the two sliding brackets 21. The adjustment mechanism 9 includes a mounting block 91 fixedly provided on one side of the two sliding brackets 21. The inner sides of the two mounting blocks 91 are both threadedly connected to screw rods 92. The front ends of the two screw rods 92 are both fixedly provided with a limiting column 93. The rear ends of the two screw rods 92 are both fixedly provided with a knob 94.

[0125] Please combine Figure 12 : Rotate the two knobs 94 to drive the two screws 92 to rotate forward. The two screws 92 move forward to drive the two limit posts 93 to move forward. The limit posts 93 can be used to limit the moving distance of the movable seat 22.

[0126] Preferably, by adjusting the positions of the two limiting posts 93 , the rearmost position reached by the movable seat 22 can be adjusted, and thus the working position of the sample holder 6 can be adjusted.

[0127] The top of the processing box 1 is connected to a conical bucket 10, and a cover plate 11 is provided on the top of the conical bucket 10. Two support blocks 12 are fixed at the bottom of the processing box 1 and the spectrometer body 7;

[0128] Preferably, when the two extrusion blocks 34 are respectively located on both sides of the circular through hole in the sample holder 6, forming a blocking state for the circular through hole, when the pointer 86 rotates 45 degrees counterclockwise, the conical bucket 10 is connected to the circular through hole opened in the sample holder 6 through the cylindrical through hole, and the conical bucket 10 is used to discharge powdered samples.

[0129] In this embodiment, when the movable base 22 drives the sample holder 6 to move forward, the movement of the movable base 22 drives the gear plate 84 to move forward, and the gear plate 84 then drives the gear 83 to rotate counterclockwise, and the gear 83 then drives the pointer 86 to rotate counterclockwise through the rotating shaft 82. By observing the rotation position of the pointer 86 in the display dial 85, the degree of extrusion of the powder sample by the two extrusion blocks 34 can be seen, and by observing the counterclockwise rotation position of the pointer 86 in the display dial 85, it can be seen whether the conical bucket 10 is connected to the cylindrical through hole, which is convenient for the operator to feed the powder sample.

[0130] Please refer to the Figures 1 to 13 The working principle of the compensation method for abnormal measurement laser pulse in the Fourier transform infrared spectrometer provided by the present invention is as follows:

[0131] Step S1: When the pointer 86 rotates 45 degrees counterclockwise within the display dial 85, the two squeezing blocks 34 are located on either side of the circular through hole in the sample holder 6, forming a blocking state for the circular through hole. Then, the powdered sample is dropped into the circular through hole in the sample holder 6 through the conical hopper 10.

[0132] In step S2, the driving motor 24 is started, and the threaded screw 23 is driven to rotate by the driving motor 24, and the threaded screw 23 is driven to move forward by the rotation of the threaded screw 23, and the movable seat 22 and the sample holder 6 are moved forward. The sample holder 6 drives the two movable plates 32 to move forward inside the processing box 1 through the raised baffles on both sides. During the movement, the two movable plates 32 drive the extrusion rods 33, the extrusion blocks 34, the rotating frame 36 and the rotating wheel 37 to move forward. Under the action of the two trapezoidal plates 38, the two rotating wheels 37 will cause the two extrusion rods 33 to move to the opposite side during the movement, and cause the two springs 35 to contract. The two extrusion rods 33 move to the opposite side, and the two extrusion blocks 34 move to the opposite side. As the movable seat 22 gradually moves forward, the two extrusion blocks 34 are slowly inserted into the circular through holes in the sample holder 6, and finally the powdered sample is pressed into thin slices.

[0133] In step S3, the threaded screw 23 drives the movable seat 22 and the sample holder 6 to move forward, and at the same time drives the gear plate 84 to move forward. The movement of the gear plate 84 drives the gear 83 to rotate counterclockwise. The gear 83 drives the pointer 86 to rotate counterclockwise via the rotating shaft 82. By observing the rotation position of the pointer 86 in the display dial 85, the degree of compression of the powder sample by the two squeezing blocks 34 can be seen. When the squeezing force for the powder sample is reached, the drive motor 24 is turned off, and the pressure on the powder sample is kept constant until the tableting requirement is met.

[0134] Step S4, when the tableting of the powdered sample is completed, the driving motor 24 is started, and the threaded screw 23 is used to drive the movable seat 22 and the sample holder 6 to move backward. The movement of the sample holder 6 drives the extrusion block 34, the extrusion rod 33, the rotating frame 36 and the rotating wheel 37 to move backward, and at the same time, the two movable plates 32 slide backward on the inner side of the processing box 1. In the process of the movable seat 22 driving the sample holder 6 to move gradually backward, the expansion of the spring 35 causes the two extrusion blocks 34 to gradually disengage from the circular through-holes in the sample holder 6. After disengagement, the movable seat 22 alone drives the sample holder 6 and the thin slice sample to move into the spectrometer body 7, and then the spectrometer body 7 is used to detect the thin slice sample;

[0135] When the movable base 22 drives the sample holder 6 to move backward, it also drives the gear plate 84 to move backward. The gear plate 84 moves backward, which in turn drives the gear 83 to rotate clockwise. When the gear plate 84 separates from the gear 83, the pointer 86 rotates clockwise to the 0 degree position of the display dial 85.

[0136] In step S5, after the thin slice sample is tested, the cover on the top of the spectrometer body 7 is opened, and the sample holder 6 is pulled out upwards, cleaned or replaced, and the top position of the movable plate 32 is slid to the last position of the inner groove on the top of the processing box 1 by the raised block, and the position of the movable plate 32 is reset to facilitate the next test of the powder sample.

[0137] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for compensating for abnormal measurement laser pulses in a Fourier transform infrared spectrometer, characterized in that: It includes a control module, a time window calculation module, a timer module and an ADC trigger pulse generation module; The control module is used to control the operation process of the entire solution; The time window calculation module is used to calculate the effective time window, and its calculation logic is as follows: S1: After reset, the default effective time window is set according to the moving mirror stabilization speed + fluctuation; The designed measuring laser pulse wavelength is λnm, and the target optical path difference change speed caused by the moving mirror is vcm / s. According to the two zero-crossing pulses generated by each measuring laser wavelength, the ideal time interval of the measuring laser pulse is: The actual moving mirror will not produce an optical path difference at the ideal vcm / s speed due to reasons such as the drive circuit and mechanical vibration. Generally, it is required to be controlled within 2%. Leave a certain margin and set the time window of the metering pulse according to 2 times, that is, ±4%. The time window is set to: A HeNe laser with a wavelength of 632.8 nm is used as the metering laser. Based on the ideal optical path difference of 1 cm / s, the time window of the metering pulse is set at ±4%, that is, 30.3 µs to 32.9 µs. If the next metering pulse arrives within this time range, it is considered a valid pulse. S2: For the "missing pulse situation", since the supplementary generated pulse has exceeded the valid time window, the next valid time window should be set closer; However, in order to facilitate unified processing, the effective time window remains unchanged, but the advance amount of half a time window is increased to the "timer module", that is, the starting point of the next timer module is set to The timer module is used to calculate the effective time window, and its operating logic is as follows: S1: After receiving the "start" command from the control module, the timing starts from the preset timing starting point. When running at a main frequency of 100MHz, the timing accuracy reaches 10ns; S2: After receiving the "reset / clear" command from the control module, the timer module stops timing and the duration is cleared; S3: After receiving the "add advance" command from the control module, the corresponding advance is added to the starting point of the timer module. This function will be used in the case of "missing pulse"; The ADC trigger pulse generation module is used to generate a trigger signal that ultimately drives the ADC to collect infrared interferograms. Its operating logic is as follows: S1: The control module determines that the current original pulse is within the "valid time window", and this module outputs an ADC trigger pulse; S2: The control module determines that the current original pulse is earlier than the "valid time window", and this module discards the original pulse and does not generate an ADC trigger pulse; S3: If the control module determines that no new pulse arrives after the effective time window ends, this module generates another pulse and outputs it as an ADC trigger pulse.

2. The method for compensating for abnormal measurement laser pulses in a Fourier transform infrared spectrometer according to claim 1, characterized in that: The Fourier infrared spectrometer is mainly composed of an infrared light source, a measuring laser, an interferometer, a sample to be measured, a measuring laser pulse generation circuit, an infrared signal ADC acquisition circuit, and a computer.

3. The method for compensating for abnormal measurement laser pulses in a Fourier transform infrared spectrometer according to claim 2, wherein: Compared with the traditional Fourier infrared spectroscopy structure, the newly added control module, time window calculation module, timer module and ADC trigger pulse generation module are used to intercept and reprocess the original pulses generated by the metering laser pulse generation circuit. After processing, the pulses that are confirmed to be free of abnormalities are then used for infrared signal ADC acquisition.

4. The method for compensating for abnormal measurement laser pulses in a Fourier transform infrared spectrometer according to claim 3, wherein: The improved spectrometer based on the compensation method for the abnormal measurement laser pulse in the Fourier transform infrared spectrometer requires the use of a processing box, a linear motion mechanism and an extrusion mechanism when testing powder samples; The linear motion mechanism includes two sliding brackets fixedly mounted on the bottom of the inner wall of the processing box, and a moving seat is slidably connected to the opposite side of the two sliding brackets. The inner side of the moving seat is threadedly connected to a threaded screw, and the front end of the threaded screw is rotatably connected to the front side of the inner wall of the processing box. A driving motor for driving the threaded screw to rotate is provided on the front side of the processing box; The extrusion mechanism includes two guide rods fixedly arranged on the inner side of the top of the processing box, the surfaces of the two guide rods are slidably connected to movable plates, the surfaces of the tops of the two movable plates are slidably connected to the inner side of the processing box, the inner sides of the two movable plates are slidably connected to extrusion rods, the opposite ends of the two extrusion rods and the opposite sides of the two movable plates are fixed with extrusion blocks, the surfaces of the two extrusion rods and the sides of the two movable plates separated are sleeved with springs, the separated ends of the two extrusion rods are fixed with rotating frames, the inner sides of the two rotating frames are rotatably connected to rotating wheels, and trapezoidal plates are fixed on both sides of the inner wall of the processing box.

5. The method for compensating for abnormal measurement laser pulses in a Fourier transform infrared spectrometer according to claim 4, characterized in that: Two clamping frames are fixedly provided on the top of the movable seat, two card blocks are fixedly provided on opposite sides of the two clamping frames, sample clamps are provided on opposite sides of the two clamping frames, and the surfaces of the sample clamps are slidably connected to the surfaces of the card blocks. The spectrometer body is fixedly provided on the back of the processing box.

6. The method for compensating for abnormal measurement laser pulses in a Fourier transform infrared spectrometer according to claim 4, characterized in that: A sliding groove is provided on the inner side of the top of the processing box for use with the two movable plates to allow the two movable plates to slide back and forth. A groove is provided on the surface of the two extrusion rods for horizontal sliding on the inner side of the movable plate. The surfaces of the two rotating wheels are respectively in contact with the surfaces of the two trapezoidal plates.

7. The method for compensating for abnormal measurement laser pulses in a Fourier transform infrared spectrometer according to claim 5, characterized in that: The two extrusion blocks are cylindrical, and a circular through hole for use with the two extrusion blocks is opened on the inner side of the sample clamp. A cylindrical through hole is opened vertically on the inner side of the sample clamp, and the cylindrical through hole is connected to the circular through hole.

8. The method for compensating for abnormal measurement laser pulses in a Fourier transform infrared spectrometer according to claim 4, characterized in that: A pressure display mechanism is fixedly provided on the left side of the bottom of the inner wall of the processing box, and the pressure display mechanism includes a rotating bracket fixedly provided on the left side of the bottom of the inner wall of the processing box, and the inner side of the rotating bracket is horizontally rotatably connected with a rotating shaft, and the right end of the rotating shaft is fixedly provided with a gear, and a gear plate is fixedly provided on the left side of the top of the movable seat, and the gear is engaged with the gear plate. A display dial is fixedly provided on the left side of the processing box, and a pointer is provided inside the display dial. The left end of the rotating shaft is fixedly connected to the right side of the pointer.

9. The method for compensating for abnormal measurement laser pulses in a Fourier transform infrared spectrometer according to claim 4, wherein: An adjustment mechanism is fixed on one side of the two sliding brackets, and the adjustment mechanism includes a mounting block fixed on one side of the two sliding brackets. The inner sides of the two mounting blocks are threadedly connected with screws, the front ends of the two screws are fixed with limit columns, and the rear ends of the two screws are fixed with knobs.

10. The method for compensating for abnormal measurement laser pulses in a Fourier transform infrared spectrometer according to claim 5, characterized in that: The top of the processing box is connected to a conical bucket, the top of the conical bucket is provided with a cover plate, and the bottoms of the processing box and the spectrometer body are both fixed with two supporting blocks.

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