CN208999305U - Laser gas detection device - Google Patents
Laser gas detection device Download PDFInfo
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- CN208999305U CN208999305U CN201821662980.1U CN201821662980U CN208999305U CN 208999305 U CN208999305 U CN 208999305U CN 201821662980 U CN201821662980 U CN 201821662980U CN 208999305 U CN208999305 U CN 208999305U
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Abstract
The utility model provides a kind of laser gas detection device, by the way of the scanning of multiple Laser synchronisations, the higher laser light source group of transmission power can be formed using laser, light-dividing device is utilized simultaneously, the beam splitter that every road laser is launched is reference light and detection light, by being detected to absorption peak present position in the reference light after gas absorption cell, and independently the length scanning of each laser is adjusted according to detection information, and then adjust absorption peak relative position locating in the laser signal eventually received, solve the problems, such as the deterioration of signal quality.
Description
Technical field
The utility model relates to gas analysis detection fields, and in more detail, the utility model relates to a kind of laser gases
Detection device.
Background technique
T unable filter (TDLAS) be it is a kind of by laser be applied to absorption spectrum measuring technique
Optics and spectroscopy measurements method.TDLAS is absorbed using semiconductor laser narrow linewidth and the characteristic quickly tuned by detection
One isolated vibration of molecule turns Absorption Line, and the quick detection to gas may be implemented.
Using TDLAS technology to gas concentration measure using very extensive, including atmospheric detection, vehicle exhaust are surveyed
It measures, hazardous gas spillage detects, gas concentration measurement etc. in flue.Some specific application scenarios (such as from bottom of the building to residence
People building high level carry out Leakage inspection or carry out gas concentration measurement on a surface target using unmanned plane) in often need using spy
Ranging is from farther away laser gas detection device.
In order to increase detection range, fraction of laser light gas-detecting device increases in such a way that multiple lasers work at the same time
Transmission power, however, in the process of implementing the utility model, although inventors have found that merely improving the quantity of laser
Transmission power can effectively be increased, but bring following problems simultaneously: being obtained with the increase for using the time, detection device
Laser signal total quality serious deterioration.
Utility model content
In view of the above problem of the prior art, the utility model provides a kind of laser gas detection device, can be to old
Multiple lasers after change carry out the correction of individual length scanning, and the absorption peak that the road Shi Ge laser is formed after being collected can be very
It is superimposed well, laser signal total quality is reduced or prevented to deteriorate.
During founding the utility model, inventors have found that the deterioration of laser signal total quality is derived mainly from always
Change the variation of the scanning range of bring length scanning.The variation of wavelength scanning range can cause absorption peak in different laser spectrums
Is there is swarming phenomenon by the drift of position, the absorption peak after drift in the Signal averaging result for making laser, which will
The analysis for influencing light intensity signal, ultimately causes the deterioration of signal quality.
To solve the above-mentioned problems, the laser gas detection device that the technical solution of the utility model provides includes: multiple
Laser；Control unit is electrically connected with multiple lasers, can control the length scanning that multiple lasers synchronize, gas to be measured
The central wavelength at body target absorption peak is preset in the sweep waveform of length scanning and occupies the first relative position；One or more point
The emitting light path of light component, multiple lasers passes through light splitting part, is detection by the laser beam splitter of each laser emitting
Light and reference light；One or more gas absorption cells, the optical path of each road reference light pass through gas absorption cell, in gas absorption cell
Filled under test gas；One or more detectors configure in the optical path in each road reference light after gas absorption cell；Control unit
It is electrically connected with detector, can determine that the target absorption peak of under test gas accounts in the light intensity signal waveform that detector collects
According to the second relative position；Control unit further includes position correction module, and position correction module is electrically connected with multiple lasers, can
According to the second relative position deviate the first relative position bias, independently to the length scanning of one or more lasers into
Row is adjusted.
Multiple laser combinations can produce the higher laser light source of transmission power, technical solution provided by the utility model
The signal quality problem generated to eliminate multiple laser combinations, using position correction module to various lasers because of aging
And the absorption peak deviation generated is corrected, and final main detector is enable to receive absorption in the identical or essentially identical time
Peak-to-peak signal prevents from being finally superimposed the laser signal generation swarming phenomenon generated, effectively increases the total quality of laser signal, prevent
The only serious deterioration of overall signal quality caused by section laser aging.
In the more excellent technical solution of the utility model, laser gas detection device includes current driving device, and electric current drives
Dynamic device is electrically connected with multiple lasers and control unit, and the control signal that can be exported according to control unit carries out current scanning, with
Multiple lasers are driven to carry out length scanning.Current regulation mode realizes length scanning by changing the Injection Current of laser
Adjusting, have high governing response speed and lower installation cost.
Further, in the more excellent technical solution of the utility model, position correction module includes current correction unit, electricity
Stream correction unit is electrically connected with current driving device, the current scanning range of current driving device can be adjusted, to laser
Length scanning be adjusted.Position correction is carried out using current correction unit, there is the high speed of response and accuracy.This
Outside, current scanning range is corrected using current correction unit, device modification difficulty and cost is relatively low.
Further, in the more excellent technical solution of the utility model, the sweep waveform of current scanning be triangular wave or
Sawtooth wave, current correction unit by the basis of sweep waveform be superimposed constant amplitude amount of bias, with according to laser device laser wavelength with
The corresponding relationship of driving current adjusts accordingly the scanning range of length scanning.In some embodiments, described to adjust accordingly
The scanning range of length scanning, which refers to, translates the scanning range of length scanning.It is carried out using triangular wave or sawtooth waveform
Current scanning can linearly be adjusted the scanning range of wavelength, facilitate the calculating of adjustment amount.
Optionally, control unit further includes current offset amount computing unit, can deviate the first phase according to the second relative position
Bias to position obtains constant amplitude amount of bias.
In the more excellent technical solution of the utility model, the temperature of laser is adjustable, and position correction module includes temperature
Unit is corrected, temperature correction unit can input temperature control electric current to laser, to close according to laser wavelength is corresponding with temperature
System, is adjusted the length scanning of laser.Using temperature regulation mechanism, it is capable of the scanning of adjusting wavelength in a big way
Range, so that laser gas detection device copes with absorption peak and deviates more serious situation.
Further, in the more excellent technical solution of the utility model, laser includes temperature sensor, temperature correction list
Member is electrically connected with temperature sensor, can be according to the temperature of the laser that temperature sensor obtains, the second relative position deviation the
The bias of one relative position exports temperature control electric current to laser.Temperature tune is carried out using the laser with temperature sensor
Section, can cooperate wavelength and temperature, the relationship of electric current more accurately, adjust the length scanning of laser.
In the more excellent technical solution of the utility model, laser gas detection device further includes laser module bracket, laser
Assembly support has multiple parallel arrangement of carrier units, and carrier unit and light splitting part, gas absorption cell and detector are pacified
Dress is fixed, and one or more detectors are electrically connected to same circuit board, and circuit board is installed on the shell of laser gas detection device
Body.By the above mounting means, the heat dissipation performance of circuit board is effectively promoted.
Further, in the more excellent technical solution of the utility model, laser module bracket is installed with multiple lasers
Mouthful, multiple lasers pass through laser installing port and the removable connection of laser module bracket.Conveniently in section laser failure
Replacement in time, while the quantity selection of laser can be easily adjusted, to cope with the different number of lasers using under situation
It is required that improving the universality of laser gas detection device.
In the more excellent technical solution of the utility model, laser gas detection device includes: multiple lasers；Control unit,
It is electrically connected with multiple lasers, the length scanning that multiple lasers synchronize can be controlled, under test gas target absorption peak
Central wavelength is preset in the sweep waveform of length scanning and occupies the first relative position；Current driving device, current driving device
It is electrically connected with multiple lasers and control unit, the control signal that can be exported according to control unit carries out current scanning, more to drive
A laser carries out length scanning；One or more light splitting parts pass through light splitting part on the emitting light path of multiple lasers,
To be detection light and reference light by the laser beam splitter of each laser emitting；One or more gas absorption cells, each road reference light
Optical path on pass through gas absorption cell, filled under test gas in gas absorption cell；One or more detectors configure on each road
Reference light is in the optical path after gas absorption cell；Control unit is electrically connected with detector, can determine that the target of under test gas is inhaled
Receive the second relative position that peak occupies in the light intensity signal waveform that detector collects；Control unit further include: position correction
Module, position correction module are electrically connected with multiple lasers, and it is opposite can to deviate described first according to second relative position
The bias of position is independently adjusted the length scanning of one or more lasers；Position correction module includes electric current
Correction unit and temperature correction unit, current correction unit are electrically connected with current driving device, can adjust current driving device
Current scanning range, temperature correction unit can to laser input temperature control electric current, with to laser length scanning carry out
It adjusts；Position correction module is preset with adjusting threshold value, adjusts if the bias that the first relative position is deviateed in the second relative position is less than
Threshold value is saved, position correction module carries out position correction using current correction unit；If the first opposite position is deviateed in the second relative position
The bias set, which is greater than, adjusts threshold value, and position correction module uses temperature correction unit and electricity using temperature correction unit or simultaneously
Stream correction unit carries out position correction.
In this more excellent technical solution, the position correction module of laser gas detection device use simultaneously temperature correction unit and
Current correction unit is corrected the wavelength scanning range of laser, when absorption peak bias is smaller, passes through correction rate
Comparatively fast and more accurate current correction unit is corrected, and when absorption peak bias is larger, opening temperature corrects unit,
The length scanning state of correcting laser in biggish adjustable range.In the above manner, the laser gas detection device energy
It is enough to be pointedly adjusted correction according to different aging conditions, while meeting adjustment speed, degree of regulation and adjusting model
The requirement enclosed.
The utility model additionally provides a kind of bearing calibration of laser gas detection device, for being equipped with multiple lasers
Laser gas detection device, the bearing calibration the following steps are included:
The length scanning that multiple lasers synchronize, wherein the central wavelength under test gas target absorption peak is in wavelength
It is preset in the sweep waveform of scanning and occupies the first relative position；
It is detection light and reference light by the laser beam beam splitting of multiple laser emittings；
Multichannel reference light is passed through into the gas absorption cell filled under test gas；
Light intensity signal by the road gas absorption cell Hou Ge reference light is detected；
Determine the second relative position that the target absorption peak of under test gas occupies in reference light light intensity signal waveform；
The bias for deviateing the first relative position according to the second relative position, independently to the wave of one or more lasers
Long scan is adjusted.
Detailed description of the invention
Fig. 1 is the photoconductive structure signal of the laser module of the laser gas detection device in the utility model one embodiment
Figure；
Fig. 2 is the waveform diagram of driving current signal in Fig. 1 embodiment；
Fig. 3 is the waveform diagram of Fig. 1 embodiment medium wavelength scanning signal；
Fig. 4 is the laser signal waveform diagram of the laser in Fig. 1 embodiment after the received aging of detector；
Fig. 5 is that the structure of the feedback control loop of the laser gas detection device in another embodiment of the utility model is shown
It is intended to；
Fig. 6 is the mounting structure schematic diagram of the laser module in Fig. 1 embodiment；
Fig. 7 is position school of the laser gas detection device in one embodiment of the utility model for realizing laser
Positive structural schematic diagram；
Fig. 8 is the operation method flow chart of the position correction structure in Fig. 7 embodiment.
Appended drawing reference:
100- laser, 102- light splitting part, 104- gas absorption cell, 106- detector, 108- circuit board, 200- control
Portion, 202- position correction module, 206- analog-to-digital conversion module, 2020- bias computing unit, 2022- current offset amount calculate
Unit, 2024- temperature control current calculation unit, 2026- current correction unit, 2028- temperature correction unit, 300- laser, 302-
Detect light, 304- reference light, 400- current driving device, 500- laser module bracket, 502- carrier unit, 504- laser peace
Fill mouth, 506- collimation lens.
Specific embodiment
As stated in the background art, due to the power limited of laser, in order to increase the detection of laser gas detection device away from
From technical staff can realize in such a way that multiple lasers work at the same time.However, the quantity for merely improving laser is same
When can bring certain problem, i.e., with the aging of instrument, the total quality deterioration of laser signal is obvious.
In the process of implementing the utility model, inventor has found the technical problem by the research to the technical problem
It is derived mainly from the variation of the scanning range of aging bring length scanning, and then causes the drift for absorbing peak position, after drift
Is there is swarming phenomenon by absorption peak in the Signal averaging result for making each laser, which will affect point of light intensity signal
Analysis, causes the total quality of laser signal to deteriorate.
Specifically, when leaving the factory, each laser is configured as executing the wavelength of stringent synchronization laser gas detection device
Scanning.In some embodiments, the multiple laser is the electric current tuning laser of same model, by controlling each laser
Driving current synchronous scanning, so that multiple lasers is executed the synchronous and identical length scanning of scanning range.The wavelength of the synchronization
Scanning process can be by strict implement, but with the increase for using the time when instrument just dispatches from the factory, and each electric current tuning laser will go out
Now different degrees of aging, aging phenomenon change the wavelength for making electric current tuning laser-electric current correlation function.Along with
Although the generation of aging phenomenon, each laser are loaded with synchronous sweep current, but obtained wavelength scanning range and endless
Complete synchronous, wavelength-electric current correlation function of section laser changes greatly, causes in same scan cycle, specific absorption wave
It is different to grow the position occupied in length scanning.At this point, will divide in same period in the laser signal that photodetector is collected into
The laser signal of multiple absorption peaks out, this form is second-rate, will seriously affect subsequent gas concentration analysis.
For example, in one embodiment, selecting central wavelength is the absorption line of 1653.72nm, corresponding temperature
Value is 22.9 DEG C, current value 70mA；Laser scans 20-120mA range, wherein the corresponding wavelength value of 20mA be
1653.478nm, and the corresponding current value of 120mA is 1654.076nm, when leaving the factory, the central wavelength of absorption line is (corresponding
70mA current value) will ply in the centre position in wavelength scan curve, i.e. the position 1/2T；And when aging occurs for laser, 20-
The current value scanning range of the 120mA wavelength scanning range that correspondence is different, and then cause the central wavelength of 1653.72nm corresponding
Current value will also change, such as 50mA, at this point, absorption peak is located at the position 1/4T, if the absorption peak of another laser is still
Keep in situ, then the photodetector of final instrument will detect that gas absorbs letter in same period at the sampled point of different time
Number, that is, multiple absorption peaks for occupying different location will be presented in the laser signal being collected into one cycle, seriously affect subsequent
The calculating of gas concentration is analyzed.
By analyzing above, inhaled inventors have found that the deterioration of laser signal quality is originated from caused by section laser aging
Receive mutually being staggered for peak position.To solve the above-mentioned problems, the utility model provides a kind of laser gas detection device, packet
It includes: multiple lasers；Control unit is electrically connected with multiple lasers, can control the length scanning that multiple lasers synchronize,
The central wavelength under test gas target absorption peak is preset in the sweep waveform of length scanning and occupies the first relative position；Spectrum part
Part is provided with light splitting part on the emitting light path of multiple lasers, is detection by the laser beam splitter of each laser emitting
Light and reference light；Gas absorption cell, is provided with gas absorption cell in the optical path of each road reference light, in gas absorption cell filled with to
Survey gas；Detector, each road reference light are provided with detector in the optical path after gas absorption cell；Control unit and detector
Electrical connection, can determine the target absorption peak of under test gas occupies in the light intensity signal waveform that detector collects second
Relative position；Control unit further includes position correction module, and position correction module is electrically connected with multiple lasers, in response to the second phase
To position deviate the first relative position, position correction module can the length scanning independently to corresponding laser adjust
Section.
By the way of the scanning of multiple Laser synchronisations, the higher laser of transmission power can be formed using multiple lasers
Light source group, while light-dividing device is utilized, the beam splitter that every road laser is launched is reference light and detection light, by warp
Absorption peak present position is detected in reference light after crossing gas absorption cell, and according to detection information independently to each laser
The length scanning of device is adjusted, and then adjusts absorption peak relative position locating in the laser signal eventually received, solution
The certainly deterioration problem of signal quality.
Hereinafter, generaling description the preferred embodiment of the utility model on one side referring to attached drawing while.In addition, the utility model
Embodiment is not limited to following embodiments, can be using the various realities in the range of the technology design of the utility model
Apply example.
Embodiment one
A kind of laser gas detection device is present embodiments provided, as shown in Figure 1, the laser gas detection device includes more
A laser 100, each laser 100 are configured with independent control loop, carry out for the length scanning state to laser
It adjusts.
Specifically, it is provided with light splitting part 102 in the control loop of every laser 100, which can incite somebody to action
300 beam splitting of laser that laser 100 projects is detection light 302 and reference light 304.Wherein, 102 surface of light splitting part is coated with anti-reflection
Film, to further increase detection 302 light intensity of light.In the present embodiment, 101 surface of light splitting part plating anti-reflection film can make to detect light
302 with reference light 304 have 99:1 or more beam intensity ratio, reference light 304 due to detection light 302 through same 300 beam splitting of laser
It obtains, can be used as the sample of analysis detection 302 state of light, the length scanning state of detection light 302 is monitored.
Reference light 304 be separated out after path on be provided with gas absorption cell 104, filled with to be measured in gas absorption cell 104
Gas, after reference light 304 passes through gas absorption cell 104, the light of specific wavelength can be absorbed by gas-selectively, carry gas suction
The reference light 304 ceased of collecting mail is received by detector 106.Detector 106 is converted to the light intensity signal of the reference light 304 received
Electric signal is sent to control unit 200, and control unit 200 can carry out modulus to the electric signal of reflection 304 intensity signal of reference light and turn
It changes, and generates driving signal based on the analysis results, to control the length scanning state of laser 100, the above structure is constituted to sharp
The control loop that light device 100 is split, detects, feeds back and controls.
In the present embodiment, the under test gas of laser gas detection device target measurement is methane gas, and reference light 304 is passing through
After crossing methane gas, characteristic absorption will be generated near 1653.72nm, and interference is not present near the central wavelength and absorbs
Peak, therefore select using 1653.72nm to be the absorption peak of center wavelength as the target absorption peak of under test gas in the present embodiment.It should
For laser gas detection device in such a way that multiple laser synchronizations scan, the laser that can be readily able to obtain is combined into transmitting function
The higher laser light source group of rate, to cope with the natural gas leaking inspection under some specific environments, such as from bottom of the building to residential building height
Layer carries out natural gas leaking detection or carries out gas pipeline leakage inspection etc. on a surface target using unmanned plane.Certainly, originally
The technical staff in field can also design the laser gas detection device for different under test gas according to actual needs, can
The under test gas of choosing includes the gases such as ammonia, carbon monoxide, hydrogen.It, can also be in addition, technical staff is for same under test gas
Select the different absorption peaks of under test gas as target absorption peak, it is only necessary to the type of laser, laser wavelength scanning
The parameters such as central wavelength, scanning range are adjusted.
Below with reference to Fig. 2-Fig. 4, control loop provided in this embodiment is further described to 100 length scanning of laser
Control mode.The laser 100 that laser gas detection device in the present embodiment uses is electric current tuning laser, control unit
200 being capable of the current modulated that applies to each laser 100 of independent control.
In the present embodiment, current modulated carries out low-frequency sweep using sawtooth signal.With reference to Fig. 2, factory preset
The minimum value for the driving current that low-frequency sweep signal obtains is 20mA, maximum value 120mA, and driving laser 100 carries out linearly
Or substantially linear length scanning, the sweep waveform of corresponding length scanning are as shown in Figure 3.Under test gas target absorption peak
Central wavelength be 1653.72nm, the working current value of laser 100 corresponding with the wavelength is 70mA.That is, target absorption peak
Central wavelength the position that the first relative position for occupying was 1/2 period is preset in the sweep waveform of length scanning.This implementation
In example, the first relative position referred within a scan period, the central wavelength at target absorption peak length scanning wavelength-when
The corresponding time accounts for the ratio of cycle duration T in half interval contour.
It is each although each laser 100 still loads identical synchronous scanning current signal along with the generation of aging phenomenon
For laser 100 due to the difference of degree of aging, wavelength-electric current correlation function different degrees of variation will occurs, cause final
A degree of offset occurs for the scanning curve of length scanning.The light that detector 106 changes over time the light intensity received is believed
After number being converted to electric signal, then digital signal is converted to by control unit 200, obtained light intensity (normalized)-sampled point
Curve is as shown in Figure 4.Due to aging, although the laser 100 is still driven by the electric current of 20-120mA, its wave being actually sent out
The scanning range of long scan signal drifts to 1653.582-1654.207nm.Correspondingly, central wavelength is the mesh of 1653.72nm
Mark absorption peak will also be drifted to second relative position in 1/4 period by former 1/2 period position.In the present embodiment, the second opposite position
It sets and refers to that target absorption peak sampled point n locating in sampled digital signal accounts for the total number of sample points amount N in a cycle
Ratio n/N.
It should be noted that " relative position " in the first relative position and the second relative position refers to specific absorption wavelength
Or target absorption peak is corresponding in echo signal relevant to wavelength (such as the current signal in the present embodiment, wavelength signals)
Target component (such as t, n) accounts for the ratio of the sum (such as T, N) of target component in a cycle.In other implementations of the utility model
In example, the echo signal and target component can be chosen according to the actual situation, before without departing from the utility model purport
It puts, the above variation is without departing from the protection scope of the utility model.
Laser gas detection device in order to realize the correction for the second relative position of target absorption peak, in the present embodiment
Further include position correction module 202, second relative position at target absorption peak can be corrected.Specifically, the position school
The parameter that positive module 202 adjusts is the scanning range of 100 driving current of laser.Deviateed by being independently adjustable each aging
The wavelength scanning range of the scanning range of 100 driving current of laser, the laser for issuing each laser 100 translates back originally
1653.478-1654.076nm.
In the present embodiment, the adjustment mode of the scanning range of 100 driving current of laser is in original driving current signal
On the basis of be superimposed constant amplitude amount of bias, i.e., on the basis of former driving current signal increase or reduce equal quantities electric current.Citing
For, the laser 100 of 1653.582-1654.207nm is deviated to for scanning range, position correction module 202 can be uniform
Corresponding sweep current under its each time is turned down on ground, for example, current scanning range is adjusted to 17- from original 20-120mA
117mA, so that the scanning range of wavelength be made to return to 1653.478-1654.076nm.Accordingly, due to each laser adjusted
100 wavelength scanning range is identical, and is all made of the linear scan signal that waveform is sawtooth wave, final laser gas detection device
Main detector will be collected into absorption peak-to-peak signal in the identical or essentially identical time so that the absorption of each laser 100
Peak-to-peak signal can be superimposed well, avoid absorption peak in final laser signal from falling in different relative positions, and then increase to sharp
The difficulty of optical signal analysis reduces signal quality.
It should be noted that, although in the present embodiment, each laser 100 using linear triangular wave or sawtooth signal into
Row driving, but technical staff can select other kinds of waveform to carry out length scanning, such as sine wave or group according to the actual situation
Multiplex shape etc., as long as the waveform can scan specific wave-length coverage and calculate analysis convenient for the later period.
In the present embodiment, laser 100 is electric current tuning laser.Specifically, electric current tuning laser can be sampling
Grating distributed bragg reflector lasers, auxiliary grating directional couple sample backwards reflection laser, distributed feedback laser or
Other suitably can electric current tuning laser.
In the other embodiments of the utility model, laser 100 is also possible to other kinds of tunable laser, example
Such as using the tunable laser of temperature control technology or machine control techniques.Correspondingly, to the length scanning model of laser 100
The regulative mode enclosed can also according to the actual situation, such as type, the adjustable wavelength range factor of laser 100 are adjusted
It is whole, such as use temperature adjusting, current regulation, mechanical adjustment or combinations thereof regulative mode.In addition, in other realities of the utility model
It applies in example, it is one that the components such as light splitting part 102, gas absorption cell 104, detector 106, which also can be set according to actual needs,
Or it is multiple, and shared by various lasers 100, under the premise of without departing from the utility model purport, such component count
Transformation should be understood as without departing from the protection scope of the utility model.
In the present embodiment, control unit 200 is integrated with the current source for driving laser 100, in its of the utility model
In his embodiment, each laser can also be driven using individual current driving device 400.With reference to Fig. 5, control unit 200 is wrapped
Position correction module 202 is included, the detector 106 corresponding with each laser 100 of position correction module 202 is electrically connected, Neng Gougen
Current signal is modulated according to the light intensity signal that detector 106 is collected, is had in specific modulator approach embodiment one detailed
Description, can continue to use so far, details are not described herein again.Current driving device 400 is connect with control unit 200, through position correction module 202
Modulated signal is transmitted to current driving device 400, and modulated signal includes the driving signal of each laser 100, electricity
Driving device 400 is flowed according to the driving signal, and independently each laser 100 is driven.
In addition, in other embodiments of the utility model, current driving device 400 also can be configured as one or
It is multiple, and shared by various lasers 100.Multiple lasers 100 are connect with the distinct interface of the current driving device 400,
Current driving device 400 can be independently adjusted the drive of each laser 100 according to the driving signal of the control unit 200 received
Streaming current.
In the above manner, present embodiments providing a kind of laser gas detection device, it is combined using multiple lasers 100
To generate the higher laser light source of transmission power, while various lasers 100 are produced because of aging using position correction module 202
Raw absorption peak deviation is corrected, and the relative position of the absorption peak of the road Shi Mei laser returns to preset state, to make each suction
It receives peak energy to be enough superimposed in the light intensity finally collected-sampled point signal well, improves signal quality, reduce analysis difficulty.
The present embodiment additionally provides the laser array formed in laser gas detection device by laser 100 and its mating
Feedback control components mechanical erection structure.As shown in fig. 6, laser gas detection device has for laser array and feedback
The laser module bracket 500 of control unit installation, the laser module bracket 500 include multiple parallel arrangement of carrier units 502,
Each carrier unit 502 be equipped with one piece of light splitting part, 102, gas absorption cells 104 and one to 304 light intensity of reference light into
The detector 106 of row monitoring, in addition, also there is the screw socket being threadedly engaged with laser 100, i.e., on laser module bracket 500
Laser installing port 504, can be for the removable connection of laser 100.The design of carrier unit 502 and removable laser so that
Device design and producing process is more flexible, and die cost is cheaper, and the repair and replacement of laser are also more convenient.Each laser
Device installing port 504 is arranged in parallel, so that each laser 100 for being mounted on the installing port 504 keeps emitting light path parallel, respectively
Collimation lens 506 is also equipped on the emitting light path of laser 100, to further increase the depth of parallelism of emergent light.Each road outgoing
Laser can close beam or individually project, can flexible configuration according to the actual situation.
In the present embodiment, each carrier unit 502 is also equipped with the individual circuit board 108 being electrically connected with detector 106,
Digital signal is converted to according to the analog signal that light intensity signal obtains for driving detector 106, and by detector 106, and will
Digital signal is sent to the control unit 200 of instrument.In another embodiment of the utility model, multiple detectors 106 can be with
It is electrically connected to same circuit board 108, the outer housing which may be mounted at laser gas detection device (does not show in figure
At out), to realize better heat dissipation effect.
Embodiment two
Present embodiments provide a kind of laser gas detection device, be used in combination electric current and temperature to wavelength scanning range into
Row is adjusted, and the circuit structure other than mechanical structure and position correction module can continue to use laser gas in embodiment one and examine
The dependency structure of device is surveyed, details are not described herein again.
The structure of the position correction module 202 of laser gas detection device in the present embodiment is introduced below in conjunction with attached drawing, with
And its how with the use of two kinds of electric current, temperature adjustment parameters progress wavelength calibrations.With reference to Fig. 7 and Fig. 8, swashing in the present embodiment
Laser 100 used by light gas-detecting device is the humorous laser of current adjustment, and is integrated with semiconductor system in laser 100
Cooler (Thermo Electric Cooler, TEC), by controlling the temperature control inputted to the semiconductor cooler of laser 100
Electric current can be adjusted the temperature of laser 100.
Wherein, laser 100 is 0.09nm/ DEG C to the sensitivity that length scanning is adjusted by temperature, be may be implemented
Wider wavelength regulation range, but response speed is relatively slow and inaccurate；And length scanning is carried out by changing electric current
The sensitivity of adjusting is then 0.01nm/mA, although fast response time and accurate, adjustable wave-length coverage is relatively narrow.This implementation
Example in use temperature correction unit 2028, control to laser 100 input temperature control electric current, with the wavelength to laser 100 into
Row coarse adjustment；And current correction unit 2026 is used, the current strength of control driving laser 100, with the wavelength to laser 100
It is finely adjusted.
Specifically, position correction module 202 include bias computing unit 2020, current offset amount computing unit 2022,
Temperature control current calculation unit 2024, current correction unit 2026 and temperature correction unit 2028.Wherein, detector 106 generates
Analog signal is sent to the inclined of position correction module 202 after the analog-to-digital conversion module 206 of control unit 200 carries out A/D conversion
From amount computing unit 2020.Bias computing unit 2020 calculates the bias that the first relative position is deviateed in the second relative position
Δ, according to bias Δ and the preset size relation for adjusting threshold value δ, selectively using electric current or temperature to length scanning model
It encloses and is adjusted.
When bias Δ is less than or equal to preset adjusting threshold value δ, position correction module 202 will use the side of current offset
Method carries out the fine tuning to wavelength scanning range.2020 amount of will deviate from signal of bias computing unit is sent to the calculating of current offset amount
Unit 2022, current offset amount computing unit 2022 can calculate the electric current for carrying out length scanning adjusting according to bias Δ
Constant amplitude amount of bias, and the constant amplitude amount of bias is sent to current correction unit 2026, current correction unit 2026 and electric current drive
Dynamic device 400 connects, and the constant amplitude amount of bias can be superimposed upon in primary current driving signal, realizes the tune to wavelength scanning range
Section.
When bias Δ is greater than preset adjusting threshold value δ, position correction module 202, which will use, changes 100 temperature of laser
The method of degree carries out coarse adjustment.When being adjusted using temperature, 2020 amount of will deviate from result of bias computing unit is sent to temperature control electricity
Stream calculation unit 2024, temperature control current calculation unit 2024 can be calculated according to the actual temperature of bias Δ and laser 100
The temperature control electric current finally inputted out to laser 100, and calculated result is sent to temperature correction unit 2028, by temperature correction
The output that unit 2028 executes temperature control electric current is adjusted.
It should be noted that when the bias Δ that bias computing unit 2020 is calculated is greater than preset adjusting threshold value
δ is needed to be adjusted using temperature when carrying out coarse adjustment, after completing coarse tuning process, i.e., in temperature correction unit 2028 to laser
Device 100 inputted after the step of temperature control electric current, can reacquire the analog signal of detector 106 and carry out analog-to-digital conversion, with
And Δ-δ size determination step and regulating step later, until reusing electric current when bias Δ is less than or equal to adjust threshold value δ
Correction unit 2026 is finely adjusted wavelength.
In the present embodiment, the correction course of length scanning is configured as booting operation, and closes after the completion of correction, with section
About electricity.Certainly, technical staff according to the real work situation of laser 100, can also configure the operation frequency of the correction course
Rate.
So far, it has been combined attached drawing and describes the technical solution of the utility model, still, those skilled in the art are easy reason
Solution, the protection scope of the utility model are expressly not limited to these specific embodiments.In the original without departing from the utility model
Under the premise of reason, those skilled in the art can make equivalent change or replacement to the relevant technologies feature, these are changed or replace
Technical solution after alternatively is fallen within the protection scope of the utility model.
Claims (10)
1. a kind of laser gas detection device characterized by comprising
Multiple lasers；
Control unit is electrically connected with the multiple laser, can control the length scanning that the multiple laser synchronizes, to
The central wavelength for surveying gas target absorption peak is preset in the sweep waveform of the length scanning occupies the first relative position；
The emitting light path of one or more light splitting parts, multiple lasers passes through the light splitting part, by each institute
The laser beam splitter of laser emitting is stated as detection light and reference light；
One or more gas absorption cells, the optical path of reference light described in each road pass through the gas absorption cell, and the gas is inhaled
Filled under test gas in receives pond；
One or more detectors configure the reference light described in each road in the optical path after the gas absorption cell；
The control unit is electrically connected with the detector, can determine that the target absorption peak of under test gas is acquired in the detector
The second relative position occupied in obtained light intensity signal waveform；
The control unit further includes position correction module, and the position correction module is electrically connected with the multiple laser, can
The bias for deviateing first relative position according to second relative position, independently to the wave of one or more lasers
Long scan is adjusted.
2. laser gas detection device as described in claim 1, which is characterized in that the laser gas detection device includes electricity
Driving device is flowed, the current driving device is electrically connected with the multiple laser and the control unit, can be according to the control
The control signal of portion's output processed carries out current scanning, to drive the multiple laser to carry out length scanning.
3. laser gas detection device as claimed in claim 2, which is characterized in that the position correction module includes electric current school
Positive unit, the current correction unit are electrically connected with the current driving device, can adjust the electricity of the current driving device
Scan flow range is adjusted with the length scanning to the laser.
4. laser gas detection device as claimed in claim 3, which is characterized in that the sweep waveform of the current scanning is three
Angle wave or sawtooth wave, the current correction unit on the basis of sweep waveform by being superimposed constant amplitude amount of bias, with correspondingly
The scanning range of adjusting wavelength scanning.
5. laser gas detection device as claimed in claim 4, which is characterized in that the position correction module includes that electric current is inclined
The amount of setting computing unit can deviate the bias of first relative position according to second relative position, obtain described etc.
Width amount of bias.
6. laser gas detection device according to any one of claims 1 to 5, which is characterized in that the temperature of the laser
Adjustable, the position correction module includes temperature correction unit, and the temperature correction unit can be inputted to the laser
Temperature control electric current is adjusted with the length scanning to the laser.
7. laser gas detection device as claimed in claim 6, which is characterized in that the laser includes temperature sensor,
The temperature correction unit is electrically connected with the temperature sensor, the temperature for the laser that can be obtained according to the temperature sensor
The bias that degree, second relative position deviate first relative position exports temperature control electric current to the laser.
8. laser gas detection device according to any one of claims 1 to 5, which is characterized in that the laser gas detection
Device further includes laser module bracket, and the laser module bracket has multiple parallel arrangement of carrier units, the bracket list
It is first to be fixed with the light splitting part, the gas absorption cell and detector installation, one or more detector electricity
It is connected to same circuit board, the circuit board is installed on the outer housing of the laser gas detection device.
9. laser gas detection device as claimed in claim 8, which is characterized in that the laser module bracket has multiple sharp
Light device installing port, multiple lasers pass through the laser installing port and the removable connection of laser module bracket.
10. a kind of laser gas detection device characterized by comprising
Multiple lasers；
Control unit is electrically connected with the multiple laser, can control the length scanning that the multiple laser synchronizes, to
The central wavelength for surveying gas target absorption peak is preset in the sweep waveform of the length scanning occupies the first relative position；
Current driving device, the current driving device are electrically connected with the multiple laser and the control unit, being capable of basis
The control signal of the control unit output carries out current scanning, to drive the multiple laser to carry out length scanning；
The emitting light path of one or more light splitting parts, multiple lasers passes through the light splitting part, by each institute
The laser beam splitter of laser emitting is stated as detection light and reference light；
One or more gas absorption cells, the optical path of reference light described in each road pass through the gas absorption cell, and the gas is inhaled
Filled under test gas in receives pond；
One or more detectors configure the reference light described in each road in the optical path after the gas absorption cell；
The control unit is electrically connected with the detector, can determine that the target absorption peak of under test gas is acquired in the detector
The second relative position occupied in obtained light intensity signal waveform；The control unit further include:
Position correction module, the position correction module are electrically connected with the multiple laser, can be opposite according to described second
The bias of first relative position is deviateed in position, and independently the length scanning of one or more lasers is adjusted；
The position correction module includes current correction unit and temperature correction unit, and the current correction unit and the electric current drive
Device electrical connection, can adjust the current scanning range of the current driving device, and the temperature correction unit can be to described
Laser inputs temperature control electric current, is adjusted with the length scanning to the laser；The position correction module is preset with tune
Threshold value is saved, if the bias that first relative position is deviateed in second relative position is less than the adjusting threshold value, institute's rheme
It sets correction module and position correction is carried out using current correction unit；If first relative position is deviateed in second relative position
Bias be greater than the adjusting threshold value, the position correction module using the temperature correction unit or simultaneously use the temperature
Degree correction unit and the current correction unit carry out position correction.
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| CN201821662980.1U CN208999305U (en) | 2018-10-12 | 2018-10-12 | Laser gas detection device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020073968A1 (en) * | 2018-10-12 | 2020-04-16 | 上海禾赛光电科技有限公司 | Laser gas detection apparatus and correction method therefor |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020073968A1 (en) * | 2018-10-12 | 2020-04-16 | 上海禾赛光电科技有限公司 | Laser gas detection apparatus and correction method therefor |
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