Disclosure of Invention
In order to solve the problem that the difference of two light sources affects the measurement result in the prior art, the application provides an optical detection system and an optical detection method, which improve the measurement precision of an instrument.
In a first aspect, the present application provides an optical detection system, which adopts the following technical scheme:
an optical detection system includes a light source assembly and a measurement structure assembly;
the light source assembly comprises a plurality of infrared light sources, optical fibers, an optical fiber beam combiner, a collimating lens, a first reflecting mirror and a second reflecting mirror, wherein each infrared light source is connected with one optical fiber, each optical fiber is connected with the optical fiber beam combiner, the optical fiber beam combiner is connected with the collimating lens, and the collimating lens is respectively connected with the first reflecting mirror and the second reflecting mirror;
the measuring structure assembly comprises a first sample cell, a second sample cell, a first detector and a second detector, wherein the first reflector is connected with the first sample cell, the second reflector is connected with the second sample cell, the first sample cell is connected with the first detector, and the second sample cell is connected with the second detector;
The optical fiber is used for inputting the light rays of the plurality of infrared light sources to the optical fiber combiner;
the optical fiber beam combiner is used for combining the light rays of the infrared light source and inputting the combined light rays to the collimating lens;
The collimating lens is used for adjusting the light rays of the infrared light source after beam combination into parallel light beams;
The second reflector is used for equally dividing the parallel light beam into a first parallel light beam and a second parallel light beam, the first parallel light beam irradiates the first sample cell through the first reflector and obtains a first detection light, and the second parallel light beam irradiates the second sample cell through the second reflector and obtains a second detection light;
The first detector is used for analyzing the first detection light and obtaining a first detection result;
The second detector is used for analyzing the second detection light to obtain a second detection result.
In one embodiment, the included angle between the half mirror and the parallel beam is a preset angle, the half mirror is coated with a metal film, a part of the parallel beam is reflected to the first mirror by the metal film, and the other part of the parallel beam is transmitted to the second sample cell by the metal film.
In one embodiment, the light beam reflected or transmitted by the metal film corresponds to an absorption peak of the element to be measured.
In one embodiment, the optical detection system further includes a coupling lens, the coupling lens being an aspheric lens or a plurality of spherical lenses, the coupling lens being configured to couple light rays of each of the infrared light sources into the corresponding optical fiber.
In one embodiment, the infrared light source, the coupling lens, the optical fiber combiner and the collimating lens are disposed in order along a light emitting direction of the infrared light source.
In one embodiment, the measurement structure assembly further comprises a first narrowband filter, a second narrowband filter, a first focusing lens and a second focusing lens, wherein the first sample cell, the first narrowband filter, the first focusing lens and the first detector are sequentially connected, the second sample cell, the second narrowband filter, the second focusing lens and the second detector are sequentially connected, and the first sample cell and the second sample cell are symmetrically placed and are mutually communicated through a communicating pipe.
In one embodiment, the optical detection system further comprises a sample introduction assembly connected to the first sample cell for inputting a sample to be tested into the first sample cell and the second sample cell.
In one embodiment, the sample injection assembly comprises a bottom gas inlet, a sample gas inlet, a first solenoid valve and a second solenoid valve;
The first electromagnetic valve is connected with the bottom gas inlet and is used for controlling bottom gas in the bottom gas inlet to enter the first sample pool;
the second electromagnetic valve is connected with the sample gas inlet and is used for controlling sample gas in the sample gas inlet to enter the first sample pool.
In one embodiment, the sample introduction assembly further comprises a pneumatic device coupled to the first sample cell for pressurizing the first and second sample cells.
In a second aspect, the present application provides an optical detection method, which adopts the following technical scheme:
an optical detection method, applying an optical detection system, comprising:
Inputting light rays of a plurality of infrared light sources into an optical fiber combiner through an optical fiber;
the optical fiber beam combiner is used for combining the light rays of the infrared light source and inputting the combined light rays into the collimating lens;
the light rays of the infrared light source after beam combination are adjusted into parallel light beams through the collimating lens;
dividing the parallel light beam into a first parallel light beam and a second parallel light beam by a second reflector, wherein the first parallel light beam irradiates a first sample cell by the first reflector and obtains a first detection light beam, and the second parallel light beam irradiates a second sample cell by the second reflector and obtains a second detection light beam;
analyzing the first detection light through a first detector, and obtaining a first detection result;
And analyzing the second detection light through a second detector to obtain a second detection result.
In summary, the embodiment of the invention has the following beneficial effects:
According to the optical detection system and the optical detection method, the problem of insufficient energy of the existing infrared light sources is solved by adopting the plurality of infrared light sources to couple into the optical fiber, high-power output and high-frequency modulation are realized, the optimal frequency of the detector can be matched without chopper modulation, and the two-way irradiation is realized by adopting the semi-transparent and semi-reflective lens, so that the influence of the difference of the two light sources on the measurement result in the existing scheme is solved, and the measurement precision of the instrument is improved.
In order to make the above-mentioned objects, features and advantages of the present invention more comprehensible, preferred embodiments accompanied with figures are described in detail below
Detailed Description
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the invention.
The terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the templates herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.
The human body does not have urease, helicobacter pylori (Helicobocton Pyloni, hp) can produce high-activity urease, so that the method for detecting human stomach HP is to take13 C marked urea, the urea secreted by HP can decompose the marked urea to produce13 C marked CO2, the CO2 is exhaled from the lung after blood circulation, CO2 gas exhaled by a tested person is collected, and the change of the ratio of13CO2 to12CO2 concentration before and after13 C-urea is taken is detected by a carbon-thirteen infrared spectrometer, so that whether the human body is infected with HP can be judged.
The existing detection of CO2 gas isotopes generally has optical and non-optical methods, and compared with the non-optical method, the optical method has the advantages of non-contact, high sensitivity, high selectivity, high response speed and the like. In order to balance the measurement precision of an instrument, the difficulty of a Non-professional operating the instrument, the cost of the instrument and the like, currently, non-dispersive infrared (Non-DISPERSIVE INFRARED, NDIR) is often adopted to detect the isotope abundance of carbon dioxide gas, NDIR selects absorption characteristics based on infrared spectrums of different gas molecules, and a gas sensing device for identifying gas components and determining the concentration of the gas components by utilizing the relation between the gas concentration and the absorption intensity (lambert law).
In the prior art, a blackbody radiation light source and a MEMS light source are often adopted, but the blackbody radiation light source cannot be electrically modulated, so that a chopper is often used for modulating an optical signal, which leads to increased instrument cost and reduced operation stability.
The blackbody radiation light source cannot be directly modulated, the prior proposal adopts a double light source and double detector structure, one light source is used as a reference signal, the other light source is used as a measuring signal, so as to solve the problem of low power of a single light source, and a mechanical chopper is used for solving the modulation of light signals. Although the chopper can meet the measurement requirement, the consistency of the two light sources is different and the power is low, the signal to noise ratio is high, the measurement precision and consistency of the instrument are affected, and the mechanical chopper is adopted to modulate the optical signal, so that the cost of the instrument is increased, and the long-time operation stability of the instrument is reduced.
In order to realize light source modulation, a mechanical chopper is avoided, so that the cost is reduced, however, two identical MEMS light sources are adopted for modulation, but the modulation frequency of the light sources is lower, the two light sources are different, and the detection precision is lower.
Therefore, the existing detection of the CO2 gas isotope based on the NDIR technology mainly has the problems that the single light source is low in power, the double light source structure has light source difference to influence the measurement result, the mechanical chopper is adopted to modulate the high cost and low in stability, the MEMS modulation frequency is not high, the optimal frequency adaptation with the detector is not realized, and the detection precision is low.
Example 1
Referring to fig. 1, fig. 1 is a schematic structural diagram of an optical detection system according to the present embodiment, where the system may be applied to gas isotope detection, and the system includes:
The light source assembly 100 and the measurement structure assembly 200, the light source assembly 100 comprises a plurality of infrared light sources 101, optical fibers 104, an optical fiber beam combiner 105, a collimating lens 106, a first reflecting mirror 107 and a second reflecting mirror 108, each infrared light source 101 is connected with one optical fiber 104, each optical fiber 104 is connected with the optical fiber beam combiner 105, the optical fiber beam combiner 105 is connected with the collimating lens 106, and the collimating lens 106 is respectively connected with the first reflecting mirror 107 and the second reflecting mirror 108.
Referring to fig. 2, fig. 2 is a schematic structural diagram of an array infrared LED according to the present embodiment.
The infrared light source 101 may be an array infrared LED light source, and mainly includes a PCB board, on which a plurality of LED infrared light sources 102 are disposed. The light emitting wavelength of the LED infrared light source 102 covers 4um to 4.5um, and 3X 3 LED light sources or more than 9 LED array light sources are used as the infrared LED array light sources so as to avoid insufficient energy of the light sources.
Referring to fig. 3, fig. 3 is a simulation diagram of a coupling lens according to the present embodiment.
Each LED infrared light source 102 is connected with a corresponding coupling lens 103 and optical fiber 104, so that light emitted by a plurality of LED infrared light sources 102 is collected to an optical fiber beam combiner 105 for beam combination after passing through the coupling lens 103 and the optical fiber 104, and LED light beams with higher energy are obtained, thereby solving the problem of insufficient energy of the existing infrared LED light sources, and realizing high power output and high frequency modulation.
The measurement structure assembly 200 comprises a first sample cell 201, a second sample cell 205, a first detector 204 and a second detector 208, wherein the first reflecting mirror 107 is connected with the first sample cell 201, the second reflecting mirror 108 is connected with the second sample cell 205, the first sample cell 201 is connected with the first detector 204, the second sample cell 205 is connected with the second detector 208, and the second reflecting mirror 108 is a semi-transparent half reflecting mirror.
The sample cell is mainly used for storing a sample to be tested, wherein the sample to be tested can be gas to be tested, such as gas exhaled by a target person before13 C marked urea is taken, gas exhaled by the target person after13 C marked urea is taken, and the like.
Referring to fig. 4, fig. 4 is a schematic diagram of a light path diagram of a group of coupling lenses, optical fibers and collimating lenses according to the present embodiment.
The optical fiber 104 is configured to input the light beams of the plurality of infrared light sources 101 to the optical fiber combiner 105, the optical fiber combiner 105 is configured to combine the light beams of the infrared light sources 101 and then input the combined light beams to the collimating lens 106, and the collimating lens 106 is configured to adjust the combined light beams of the infrared light sources into parallel light beams.
Since the angles of the light emitted by the different infrared light sources 101 may not be parallel light, after the light emitted by all the infrared light sources 101 is combined by the optical fiber combiner 105, the light beam needs to be adjusted into a parallel light beam by the collimating lens 106, so as to better meet the detection requirement.
The second mirror 108 is configured to divide the parallel light beam into a first parallel light beam and a second parallel light beam, where the first parallel light beam irradiates the first sample cell 201 through the first mirror 107 and obtains a first detection light, and the second parallel light beam irradiates the second sample cell 205 through the second mirror 108 and obtains a second detection light. The first detector 204 is configured to analyze the first detection light and obtain a first detection result, and the second detector 208 is configured to analyze the second detection light and obtain a second detection result.
By comparing the first detection result with the second detection result, the ratio change of13CO2 and12CO2 concentration of the target person before and after13 C-urea is taken can be determined, and whether the target person is infected with helicobacter pylori can be judged.
The PCB board adopts an electric adjustment mode to enable the frequency of the infrared LED to be in the range of 500HZ-1000HZ so as to be matched with the first detector 204 and the second detector 208, and the first detector 204 and the second detector 208 are both lead selenide detectors. The embodiment uses electrical modulation rather than mechanical chopper modulation, reducing mechanical components, reducing not only cost but also failure rate of the instrument.
In one embodiment, the included angle between the half mirror and the parallel beam is a preset angle, the half mirror is coated with a metal film, a part of the parallel beam is reflected to the first mirror 107 by the metal film, another part of the parallel beam is transmitted to the second sample cell 205 by the metal film, and the light beam reflected by the metal film or the transmitted light beam corresponds to an absorption peak of the element to be measured.
The preset angle can be 45 degrees, one surface of the semi-transparent half reflecting mirror is plated with a metal film, the other surface of the semi-transparent half reflecting mirror is a transparent glass surface, and the semi-transparent half reflecting mirror has higher light transmittance and can enable light rays reflected by the reflecting surface to be transmitted out. The element to be measured may be 12CO2 absorption peak or 13CO2.
In one embodiment, the optical detection system further includes a coupling lens 103, where the coupling lens 103 is an aspheric lens or a plurality of spherical lenses, and the coupling lens 103 is configured to couple the light of each infrared light source into the corresponding optical fiber 104.
The first surface of the coupling lens 103 has a curvature radius near the near infrared light source 101 end, the curvature radius is 2mm, the corresponding 2-order coefficient and 4-order coefficient are respectively 0.084 and-0.074, the other surface has a curvature radius of-2.5 mm, the corresponding 2-order coefficient and 4-order coefficient are respectively-0.162 and 0.045, the focal length is 4.17mm, and the material is calcium fluoride or silicon.
In one embodiment, the infrared light source 101, the coupling lens 103, the optical fiber 104, the optical fiber combiner 105, and the collimating lens 106 are disposed in this order along the light emitting direction of the infrared light source 101.
The optical fiber 104 is a mid-infrared optical fiber or a hollow core optical fiber. The focal length of the collimator lens 106 is 2mm, and the material used is calcium fluoride or silicon. The parallel light beam light spot is matched with the inner calibers of the first sample cell 201 and the second sample cell 205, and the parallel light beam light spot is less than or equal to 6mm.
In one embodiment, the measurement structure assembly 200 further includes a first narrowband filter 202, a second narrowband filter 206, a first focusing lens 203, and a second focusing lens 207, where the first sample cell 201, the first narrowband filter 202, the first focusing lens 203, and the first detector 204 are sequentially connected, the second sample cell 205, the second narrowband filter 206, the second focusing lens 207, and the second detector 208 are sequentially connected, and the first sample cell 201 and the second sample cell 205 are symmetrically placed and are mutually communicated through a communication pipe.
The first narrowband filter 202 and the second narrowband filter 206 are matched with absorption peaks of 12CO2 and 13CO2, the first sample cell 201 and the second sample cell 205 are mutually communicated through a communicating pipe, and bottom gas or sample gas can enter the second sample cell 205 through the first sample cell 201, so that both the first detector 204 and the second detector 208 can work, and errors possibly caused when a single detector is used for detection are avoided.
In one embodiment, the optical detection system further comprises a sample introduction assembly 300, wherein the sample introduction assembly 300 is connected to the first sample cell 201 for inputting a sample to be tested into the first sample cell 201 and the second sample cell 205.
The sample injection assembly 300 comprises a bottom gas inlet 302, a sample gas inlet 303, a first electromagnetic valve and a second electromagnetic valve, wherein the first electromagnetic valve is connected with the bottom gas inlet 302 and used for controlling bottom gas in the bottom gas inlet 302 to enter the first sample cell 201, and the second electromagnetic valve is connected with the sample gas inlet 303 and used for controlling sample gas in the sample gas inlet 303 to enter the first sample cell 201.
The bottom gas can be CO2 gas exhaled before13 C marked urea is taken by a user to be tested, the sample gas is CO2 gas exhaled after13 C marked urea is taken by the user to be tested, the sample injection assembly 300 further comprises a pneumatic device 301, the sample injection assembly 300 is used for collecting sample gas and bottom gas exhaled by a human body, a gas sample gas and a bottom gas sample pool are controlled through the pneumatic device 301, and 2,4, 6, 8 and 10 bottom gas inlets 302 and 303 of the sample injection assembly 300 are arranged in pairs.
The first solenoid valve and the second solenoid valve may be provided at the connection of the pneumatic device 301 with the bottom gas inlet 302 and the sample gas inlet 303 to control the opening and closing of the bottom gas inlet 302 and the sample gas inlet 303.
The pneumatic device 301 is used to pressurize the first sample cell 201 and the second sample cell 205, which can increase the absorption strength and increase the output signal strength of the detector.
According to the embodiment, the problem of insufficient energy of the existing infrared light sources is solved by adopting a plurality of infrared light source coupling entering optical fibers, high power output and high frequency modulation are realized, the optimal frequency phase adaptation of the detector can be realized without chopper modulation, and in addition, the two-way irradiation is realized by adopting the semi-transparent and semi-reflective lens, so that the influence of the difference of the two light sources on the measurement result in the existing scheme is solved, and the measurement accuracy of the instrument is improved.
Example 2
The application also provides an optical detection method applied to the optical detection system in the embodiment 1, which comprises the following steps:
Light from a plurality of infrared light sources is input to the fiber combiner through the optical fibers.
And the optical fiber beam combiner is used for combining the light rays of the infrared light source and inputting the combined light rays to the collimating lens.
And adjusting the light rays of the infrared light source after beam combination into parallel light beams through the collimating lens.
The parallel light beams are equally divided into a first parallel light beam and a second parallel light beam through a second reflector, the first parallel light beam irradiates the first sample cell through the first reflector, a first detection light beam is obtained, the second parallel light beam irradiates the second sample cell through the second reflector, a second detection light beam is obtained, and the second reflector is a semi-transparent half reflector.
And analyzing the first detection light by a first detector, and obtaining a first detection result.
And analyzing the second detection light through a second detector to obtain a second detection result.
It will be appreciated that the implementation in the optical detection system described in the above embodiment 1 is equally applicable to this embodiment, and thus the description thereof will not be repeated here.
The foregoing is merely illustrative of the present application, and the present application is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present application.
Any particular values in all examples shown and described herein are to be construed as merely illustrative and not a limitation, and thus other examples of exemplary embodiments may have different values.
It should be noted that like reference numerals and letters refer to like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.
The above examples merely represent a few embodiments of the present invention, which are described in more detail and are not to be construed as limiting the scope of the present invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention.