Compensation method for metering laser pulse abnormity in Fourier infrared spectrometer

Abstract

The invention provides a compensation method for metering laser pulse abnormity in a Fourier infrared spectrometer, which relates to the technical field of Fourier infrared spectrometers and comprises a control module, a time window calculation module, a timer and an ADC trigger pulse generation module. The control module is used for controlling the operation process of the whole scheme; and the time window calculation module is used for calculating an effective time window, and the calculation logic is as follows: S1, after resetting, default effective time window is set according to moving mirror steady rotating speed + fluctuation. According to the scheme, the measurement laser pulse loss is directly detected in a hardware circuit stage, the interference pattern data length consistency is ensured, the subsequent compensation through a complex data processing mode is not needed, the measurement laser pulse loss condition can be found, and the excessive measurement laser pulse condition caused by interference can also be found.

Description

Technical Field

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

[0002] As a vital instrument in the field of modern analytical chemistry, Fourier transform infrared spectrometer (abbreviated as FTIR) is widely used in many fields such as scientific research, industrial production and quality control. With the continuous development of technology, the performance of FTIR is also continuously improving, moving towards higher resolution, faster scanning speed and stronger sensitivity to meet the increasingly complex analysis needs, but at the same time, its internal complex optical and electronic systems are also facing new challenges. Any slight abnormality in any link may affect the accuracy of the measurement results.

[0003] The Fourier infrared spectrometer uses a metering laser to trigger the equal-path difference ADC sampling of infrared signals. This is mainly because the wavelength frequency of the metering laser is single and stable, and can be used as a scale for measuring interference signals 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 when the amplitude of the interference signal is close to 0V (also called the "zero point"), we can get equal optical path difference trigger pulses. Each pulse interval corresponds to the optical path difference between the moving mirror and the fixed mirror of the interferometer, which is half the HeNe wavelength, that is, 632.8nm / 2=316.4nm.

[0005] Since the optical path difference change of the interferometer acts equally on the infrared light and HeNe light at the same time, the optical path difference of the corresponding infrared light also changes by 316.4nm for each HeNe light zero-point pulse. Even if the zero-point pulses are not at an absolutely equal time interval due to the uneven movement speed of the moving mirror, the infrared interference signal sampling can be triggered by the HeNe light zero-point pulse, which can ensure that the infrared interference signal is sampled once every 316.4nm optical path difference, thus ensuring the accuracy of equal optical path difference sampling. Therefore, HeNe light is called a measuring scale, and frequency-stabilized lasers of other wavelengths can also be used as measuring lasers, as long as the frequency and wavelength are stable.

[0006] Since the total optical path difference L of an infrared interference pattern is roughly inversely related to the spectral resolution R, a spectral resolution of 1 cm-1 is generally 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 according to a single sampling optical path difference of 316.4 nm (the measuring laser is a HeNe laser), an interference pattern requires 31,606 sampling points and an equal number of measuring laser pulses. In addition, in some application scenarios, in order to improve the signal-to-noise ratio, multiple interference patterns are accumulated and averaged to obtain an interference pattern with a higher signal-to-noise ratio, which requires more measuring laser pulses as sampling points for the ADC.

[0007] However, in application scenarios such as factory workshops, vehicles, and satellites, 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 small area of ​​the segment, the missing trigger pulse will cause interference Figure 1 The under-sampling 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 inequality, etc., affecting usage.

[0008] Existing paper: Dutil Y, Lantagne S, Dubé S, et al. ACE-FTS Level 0To 1DataProcessing[C]. Proceedings of SPIE. 2002, 4814: 102-110. (Journal); The paper assumes that the lost metering pulse occurs in the edge area of ​​the interference pattern with a smaller amplitude, which has a smaller impact on the final spectrum (the central area with a larger amplitude has a greater impact on the final spectrum, and this central area accounts for less than 1 / 10 of the total interference pattern sequence). In the case of losing unknown h metering laser pulses, the central maximum of the interference pattern will have an overall shift of h data points, deviating from the zero point of the x-axis by h positions. This shift will eventually introduce a linear phase error related to h in the spectrum after FFT. The size of h can be obtained by simply obtaining it. By translating the interference pattern back by h positions as a whole and then performing FFT, the spectral distortion problem introduced by the loss of the metering pulse can be eliminated to a large extent.

[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 loss problem has occurred, finds the number of lost pulses, and then translates the interferogram by the same number of positions to return the center area of ​​the interferogram to the zero point of the x-axis, thereby eliminating the spectral distortion problem caused by the loss of metering pulses to a certain extent. However, this technology has the following problems:

[0011] 1. It is not possible to directly detect the loss of metering laser pulses at the hardware circuit stage, but to make up for it 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 there are extra metering laser pulses caused by interference;

[0013] 3. The only way to remedy the loss of metering pulses is to identify the number of missing data and translate the interferogram back to the zero point of the x-axis. The loss of a few small-amplitude data will not have a very obvious impact on the overall spectrum. If the metering pulse is lost in the area with a large amplitude in the center of the interferogram, the spectrum will be severely distorted and a large amount of information will be lost. There is no way to repair the problem by translating back to the zero point of the x-axis. The interferogram can only be discarded as a whole, resulting in data loss.

[0014] 4. When multiple interference pattern data need to be accumulated and averaged, this solution only translates the center area of ​​the interference pattern back to the zero point of the x-axis, which can only ensure the alignment of the area near the zero point of the x-axis. The edge area will still be misaligned. The data misalignment during the accumulation and 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 pulse in a Fourier transform infrared spectrometer, which solves the technical problem in the related art that it is inconvenient to find the loss of laser pulse 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 and an ADC trigger pulse generation module;

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

[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, the optical path difference change speed caused by the moving mirror movement is stabilized at vcm / s, and two zero-crossing pulses are generated according to 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 the driving circuit, mechanical vibration and other reasons. It is generally required to be controlled within 2%.

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

[0026]

[0027] For example, a HeNe laser with a wavelength of 632.8 nm is used as the metering laser. According to the ideal speed of the optical path difference of 1 cm / s, the time window of the metering pulse is set according to ±4%, that is, 30.3 us to 32.9 us. If the next metering pulse arrives within this time range, it is considered to be 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 "timer" is advanced by adding half a time window, that is, the starting point of the next timer is set to

[0030] The timer module is used to calculate the effective time window, and its operation 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 100 MHz, the timing accuracy reaches 10ns;

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

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

[0034] The ADC trigger pulse generation module is used to generate a trigger signal that ultimately drives the ADC to collect infrared interference patterns. Its operation 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 the module discards the original pulse and does not generate an ADC trigger pulse;

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

[0038] Preferably, the Fourier 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 (for storage, calculation and analysis of infrared interference patterns and spectrograms).

[0039] Preferably, compared with the traditional Fourier infrared spectroscopy structure, the newly added control module, time window calculation module, timer 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 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 of the measurement laser pulse anomaly in the Fourier transform infrared spectrometer needs to use a processing box, a linear moving mechanism and an extrusion mechanism when testing powder samples;

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

[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 with movable plates, the surfaces of the tops of the two movable plates are slidably connected with the inner side of the processing box, the inner sides of the two movable plates are slidably connected with extrusion rods, the opposite ends of the two extrusion rods and the opposite sides of the two movable plates are fixedly provided 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 fixedly provided with rotating frames, the inner sides of the two rotating frames are rotatably connected with rotating wheels, and trapezoidal plates are fixedly arranged on both sides of the inner wall of the processing box.

[0043] Preferably, 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, the surfaces of the sample clamps are slidably connected to the surfaces of the card blocks, and a spectrometer body is fixedly provided on the back side 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 horizontal sliding 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 used in conjunction with the two extrusion blocks is opened on the inner side of the sample clamp, a cylindrical through hole is vertically opened 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 a gear is fixedly provided on the right end of the rotating shaft, and a gear plate is fixedly provided on the left side of the top of the movable seat, and the gear is meshed with the gear plate. A display dial is fixedly provided on the left side of the processing box, and a pointer is arranged inside the display dial, and the left end of the rotating shaft is fixedly connected to the right side of the pointer.

[0047] Preferably, an adjustment mechanism is fixedly provided on one side opposite to the two sliding brackets, and the adjustment mechanism includes a mounting block fixedly provided on one side opposite to 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 fixedly provided with limit columns, and the rear ends of the two screws are fixedly provided with knobs.

[0048] Preferably, 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 fixedly provided with two supporting blocks.

[0049] Compared with the related art, the compensation method for abnormal measurement laser pulse in 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 and the excess metering laser pulses caused by interference; no matter 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 there is no need to discard the interference pattern as a whole; 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 delay deviation of the order of microseconds (us) due to the set time window problem, it can ensure 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 drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

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

[0053] Figure 2 A flow chart of the metrology laser pulse compensation 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 diagram of the structure of the bottom view of the 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 diagram of the structure 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] Fig. 9 A schematic diagram of the structure of the extrusion mechanism provided by the present invention;

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

[0062] Fig.11 A schematic diagram of the structure of the pressure display mechanism provided by the present invention;

[0063] Fig.12 A schematic diagram of a state in which the threaded screw provided by the present invention drives the moving seat and the gear plate to move forward, so that the gear drives the pointer to rotate counterclockwise through the rotating shaft;

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

[0065] Description of Figure Numbers:

[0066] 1. Processing box;

[0067] 2. Linear moving mechanism; 21. Sliding bracket; 22. Moving seat; 23. Threaded screw; 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. Clamp 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 rod; 93. Limiting column; 94. Knob;

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

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

[0074] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

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

[0076] First embodiment:

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

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

[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, the optical path difference change speed caused by the moving mirror movement is stabilized at vcm / s, and two zero-crossing pulses are generated according to 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 the driving circuit, mechanical vibration and other reasons. It is generally required to be controlled within 2%.

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

[0085]

[0086] For example, a HeNe laser with a wavelength of 632.8 nm is used as the metering laser. According to the ideal speed of the optical path difference of 1 cm / s, the time window of the metering pulse is set according to ±4%, that is, 30.3 us to 32.9 us. If the next metering pulse arrives within this time range, it is considered to be 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 "timer" is advanced by adding half a time window, that is, the starting point of the next timer is set to

[0089] The timer module is used to calculate the effective time window, and its operation 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 100 MHz, the timing accuracy reaches 10ns;

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

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

[0093] The ADC trigger pulse generation module is used to generate a trigger signal that ultimately drives the ADC to collect infrared interference patterns. Its operation 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 the module discards the original pulse and does not generate an ADC trigger pulse;

[0096] S3: When the control module determines that no new pulse arrives after the “valid time window” ends, 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 generation circuit, an infrared signal ADC acquisition circuit, and a computer (for storage, calculation, and analysis of infrared interference patterns and spectrograms).

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

[0099] Afterwards, the metering laser pulse generation circuit is responsible for converting the metering laser interference pattern into an equal optical path difference ADC acquisition trigger pulse, triggering the infrared signal ADC acquisition circuit to perform equal optical path difference sampling on the infrared light interference pattern;

[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 the 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 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 normal are then used for infrared signal ADC acquisition.

[0102] In this embodiment, compared with the existing solution that uses a data processing method to identify how many pulses are lost and make certain remedies after the abnormality has occurred, a new control module, a time window calculation module, a timer and an ADC trigger pulse generation module are added to monitor the metering laser pulses in real time from the hardware stage. When the fluctuation of the moving mirror movement speed is stabilized below 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 the time window for the next metering laser pulse to appear is predicted. When it is found that the newly generated metering pulse appears ahead of the time window, it is considered to be an extra metering pulse caused by interference, and the pulse is discarded, and the ADC is not triggered to collect the infrared interference pattern. When it is found that the time window has ended and the new metering pulse has not been generated, a metering pulse is automatically supplemented in the processor, and the ADC is triggered to collect the infrared interference pattern, so that the loss of laser pulses can be found during the collection process and compensated immediately.

[0103] Second embodiment:

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

[0105] The linear moving mechanism 2 comprises two sliding brackets 21 fixedly mounted on 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, and a threaded screw 23 is threadedly connected to the inner side of the moving seat 22, and the front end of the threaded screw 23 is rotatably connected to the front side of the inner wall of the processing box 1, and a driving motor 24 for driving the threaded screw 23 to rotate is arranged on the front side of the processing box 1;

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

[0107] Preferably, a thread groove for use with the threaded screw 23 is provided on the inner side of the movable seat 22, and the movable seat 22 can be driven to move forward and backward by the rotation of the threaded screw 23, and a groove for use with the two sliding brackets 21 is provided on the surface of the movable seat 22;

[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 with movable plates 32, the surfaces of the tops of the two movable plates 32 are slidably connected with the inner side of the processing box 1, the inner sides of the two movable plates 32 are slidably connected with squeezing rods 33, the opposite ends of the two squeezing rods 33 and the opposite sides of the two movable plates 32 are fixedly provided with squeezing blocks 34, the surfaces of the two squeezing rods 33 and the separated sides of the two movable plates 32 are sleeved with springs 35, the separated ends of the two squeezing rods 33 are fixedly provided with rotating frames 36, the inner sides of the two rotating frames 36 are rotatably connected with rotating wheels 37, and trapezoidal plates 38 are fixedly provided on both sides of the inner wall of the processing box 1;

[0109] Please combine Fig. 9 and Fig.10 : When the movable seat 22 drives the sample clamp 6 to move forward, the movement of the sample clamp 6 drives the two movable plates 32 to slide forward on the inner side of the processing box 1. 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 during the movement. 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 two squeezing rods 33 move to the opposite side and drive 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 clamp 6.

[0110] Further, when the movable seat 22 drives the sample clamp 6 to move backward, at this time, if the two squeezing blocks 34 are located in the circular through holes in the sample clamp 6, the movement of the sample clamp 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 slide backward on the inner side of the processing box 1. In the process of the movable seat 22 driving the sample clamp 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 clamp 6. After disengagement, the movable seat 22 will drive the sample clamp 6 to move backward alone.

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

[0112] Two clamping frames 4 are fixedly arranged on the top of the movable seat 22, two clamping blocks 5 are fixedly arranged on opposite sides of the two clamping frames 4, sample clamps 6 are arranged 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, and a spectrometer body 7 is fixedly arranged on the back of the processing box 1;

[0113] Preferably, a through groove 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 used in conjunction with the two movable plates 32, which is used to allow the two movable plates 32 to slide forward and backward. The surfaces of the two extrusion rods 33 are provided with grooves, which are used to slide horizontally inside 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 squeezing blocks 34 are cylindrical, and a circular through hole for use with the two squeezing blocks 34 is opened on the inner side of the sample clamp 6. A cylindrical through hole is vertically opened 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 by a tablet press and then putting them into a Fourier infrared spectrometer for detection, the present invention adjusts the two extrusion blocks 34 to the two sides of the circular through hole in the sample clamp 6 to form a blocking state for the circular through hole, and then puts the powder sample into the circular through hole through the cylindrical through hole, and drives the sample clamp 6 to move forward by the movable seat 22. Under the action of the rotating wheel 37, the rotating frame 36, the extrusion rod 33, the spring 35 and the trapezoidal plate 38, the two extrusion blocks 34 are slowly inserted into the circular through hole in the sample clamp 6, so that the powder sample is squeezed into a thin sheet by the extrusion blocks 34, and the sample clamp 6 is driven to move backward by the movable seat 22, so that the extrusion blocks 34 are separated from the sample clamp 6, so that the movable seat 22 alone drives the sample clamp 6 and the sample into the spectrometer body 7 for detection, which greatly simplifies the steps of the spectrometer body 7 for detecting powder samples, reduces the manual participation in the detection, and is suitable for batch detection of powder 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. 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. A rotating shaft 82 is horizontally rotatably connected to the inner side of the rotating bracket 81. A gear 83 is fixedly provided on the right end of the rotating shaft 82. A gear plate 84 is fixedly provided on the left side of the top of the moving seat 22. 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. A pointer 86 is arranged 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 Fig.11 and Fig.12 : When the movable seat 22 drives the sample holder 6 to move forward, the movement of the movable seat 22 drives the gear plate 84 to move forward, and the movement of the gear plate 84 drives the gear 83 to rotate counterclockwise, and 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 extrusion blocks 34 can be seen;

[0122] Furthermore, when the movable seat 22 drives the sample holder 6 to move backward, it will also drive the gear plate 84 to move backward, and the gear plate 84 will move backward to drive the gear 83 to rotate clockwise. When the gear plate 84 is separated from the gear 83, the pointer 86 will rotate 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 opposite to the two sliding brackets 21. The adjustment mechanism 9 includes a mounting block 91 fixedly provided on one side opposite to the two sliding brackets 21. The inner sides of the two mounting blocks 91 are both threadedly connected with screws 92. The front ends of the two screws 92 are both fixedly provided with a limiting column 93. The rear ends of the two screws 92 are both fixedly provided with a knob 94.

[0125] Please combine Fig.12 : Rotate the two knobs 94 to drive the two screws 92 to rotate forward, and the two limit posts 93 are driven forward by the two screws 92 to move forward. The limit posts 93 can be used to limit the moving distance of the moving 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 the working position of the sample clamp 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 fixedly provided 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 clamp 6, forming a blocked state for the circular through hole, when the pointer 86 rotates 45 degrees counterclockwise, the conical bucket 10 is connected with the circular through hole opened in the sample clamp 6 through the cylindrical through hole, and the conical bucket 10 is used to discharge the powdered sample.

[0129] In this embodiment, when the movable seat 22 drives the sample clamp 6 to move forward, the movement of the movable seat 22 drives the gear plate 84 to move forward, and the gear plate 84 drives the gear 83 to rotate counterclockwise, and 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 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 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 in the display dial 85, the two squeezing blocks 34 are respectively located on both sides of the circular through hole in the sample holder 6, and the circular through hole is blocked, and then the powdered sample is put into the circular through hole in the sample holder 6 through the conical bucket 10;

[0132] Step S2, start the driving motor 24, and drive the threaded screw 23 to rotate by the driving motor 24, and the threaded screw 23 drives the movable seat 22 and the sample clamp 6 to move forward by rotating. The sample clamp 6 drives the two movable plates 32 to move forward on the inner side of the processing box 1 through the convex baffles on both sides. The two movable plates 32 will drive the extrusion rods 33, the extrusion blocks 34, the rotating frame 36 and the rotating wheels 37 to move forward during the movement. Under the action of the two trapezoidal plates 38, the two rotating wheels 37 will move the two extrusion rods 33 to the opposite side during the movement, and make the two springs 35 contract. The two extrusion rods 33 move to the opposite side and drive the two extrusion blocks 34 to 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 clamp 6, and finally the powdered sample is pressed into a thin sheet;

[0133] Step S3, when the threaded screw 23 drives the movable seat 22 and the sample holder 6 to move forward, the gear plate 84 is driven to move forward at the same time, and the gear plate 84 moves to drive the gear 83 to rotate counterclockwise, and 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 compression blocks 34 can be seen. When the compression force of the powder sample is reached, the driving motor 24 is turned off to keep the pressure on the powder sample constant until the tableting requirement is met;

[0134] Step S4, when the tableting of the powder sample is completed, the driving motor 24 is started, and the threaded screw 23 is used to drive the moving seat 22 and the sample clamp 6 to move backward. The movement of the sample clamp 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 moving plates 32 slide backward on the inner side of the processing box 1. In the process of the moving seat 22 driving the sample clamp 6 to gradually move backward, the expansion of the spring 35 causes the two extrusion blocks 34 to gradually detach from the circular through hole in the sample clamp 6. After detachment, the moving seat 22 alone drives the sample clamp 6 and the thin sheet sample to move into the spectrometer body 7, and then the spectrometer body 7 is used to detect the thin sheet sample;

[0135] When the movable seat 22 drives the sample holder 6 to move backward, it will also drive the gear plate 84 to move backward, and the gear plate 84 moves backward to drive the gear 83 to rotate clockwise. When the gear plate 84 is separated from the gear 83, the pointer 86 will rotate clockwise to the 0 degree position of the display dial 85;

[0136] Step S5, after the thin slice sample is tested, open the flip cover on the top of the spectrometer body 7, then pull the sample clamp 6 upward, clean or replace the sample clamp 6, and slide the top position of the movable plate 32 to the last position of the inner groove on the top of the processing box 1 through the raised block, and reset the position of the movable plate 32 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 changes made by using the contents of the present invention specification and drawings under the concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for compensating 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 and an ADC trigger pulse generation module; The control module is used to control the operation process 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 according to the moving mirror stabilization speed + fluctuation; The designed measuring laser pulse wavelength is λnm, the optical path difference change speed caused by the moving mirror movement is stabilized at vcm / s, and two zero-crossing pulses are generated according to 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 the driving circuit, mechanical vibration and other reasons. It is generally required to be controlled within 2%. Leave a certain margin and set the time window of the metering pulse at 2 times, that is, ±4%. The time window is set to: For example, a HeNe laser with a wavelength of 632.8 nm is used as the metering laser. According to the ideal speed of the optical path difference of 1 cm / s, the time window of the metering pulse is set according to ±4%, that is, 30.3 us to 32.9 us. If the next metering pulse arrives within this time range, it is considered to be 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 "timer" is advanced by half a time window, that is, the starting point of the next timer is set to The timer module is used to calculate the effective time window, and its operation 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 stops timing and the duration is cleared; S3: After receiving the "add advance amount" command from the control module, add the corresponding advance amount to the starting point of the timer. This function will be used in the "missing pulse situation"; The ADC trigger pulse generation module is used to generate a trigger signal that ultimately drives the ADC to collect infrared interference patterns. Its operation 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: When the control module determines that no new pulse arrives after the "valid time window" ends, this module generates another pulse and outputs it as an ADC trigger pulse.

2. The method for compensating abnormality of measurement laser pulse in 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 tested, a measuring laser pulse generation circuit, an infrared signal ADC acquisition circuit, and a computer (for storage, calculation and analysis of infrared interference patterns and spectrum patterns).

3. The method for compensating abnormality of measurement laser pulse in Fourier transform infrared spectrometer according to claim 2, characterized in that: Compared with the traditional Fourier infrared spectroscopy structure, the newly added control module, time window calculation module, timer 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 normal are then used for infrared signal ADC acquisition.

4. The method for compensating abnormality of measurement laser pulse in Fourier transform infrared spectrometer according to claim 3, characterized in that: The improved spectrometer based on the compensation method for the abnormal measurement laser pulse in the Fourier transform infrared spectrometer as claimed in any one of claims 1 to 3 requires the use of a processing box, a linear motion mechanism and an extrusion mechanism when testing powder samples; The linear moving mechanism comprises two sliding brackets fixedly arranged at the bottom of the inner wall of the processing box, the two sliding brackets are slidably connected with a moving seat on the opposite side, the inner side of the moving seat is threadedly connected with a threaded screw, the front end of the threaded screw is rotatably connected with the front side of the inner wall of the processing box, and the front side of the processing box is provided with a driving motor for driving the threaded screw to rotate; 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 with movable plates, the surfaces of the tops of the two movable plates are slidably connected with the inner side of the processing box, the inner sides of the two movable plates are slidably connected with extrusion rods, the opposite ends of the two extrusion rods and the opposite sides of the two movable plates are fixedly provided 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 fixedly provided with rotating frames, the inner sides of the two rotating frames are rotatably connected with rotating wheels, and trapezoidal plates are fixedly arranged on both sides of the inner wall of the processing box.

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

6. The method for compensating abnormality of measurement laser pulse in Fourier transform infrared spectrometer according to claim 4, characterized in that: 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. 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 abnormality of measurement laser pulse in Fourier transform infrared spectrometer according to claim 5, characterized in that: The two extrusion blocks are cylinders, a circular through hole used in conjunction with the two extrusion blocks is opened on the inner side of the sample clamp, a cylindrical through hole is vertically opened 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 abnormality of measurement laser pulse in 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 a gear is fixedly provided on the right end of the rotating shaft, and a gear plate is fixedly provided on the left side of the top of the movable seat, and the gear is meshed with the gear plate. A display dial is fixedly provided on the left side of the processing box, and a pointer is arranged inside the display dial, and the left end of the rotating shaft is fixedly connected to the right side of the pointer.

9. The method for compensating abnormality of measurement laser pulse in Fourier transform infrared spectrometer according to claim 4, characterized in that: An adjustment mechanism is fixedly provided on one side opposite to the two sliding brackets, and the adjustment mechanism includes a mounting block fixedly provided on one side opposite to 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 fixedly provided with limit columns, and the rear ends of the two screws are fixedly provided with knobs.

10. The method for compensating abnormality of measurement laser pulse in Fourier transform infrared spectrometer according to claim 5, characterized in that: The top of the processing box is connected with 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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