CN207163908U - A kind of device of optical maser wavelength locking for gas detection - Google Patents
A kind of device of optical maser wavelength locking for gas detection Download PDFInfo
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- CN207163908U CN207163908U CN201721129522.7U CN201721129522U CN207163908U CN 207163908 U CN207163908 U CN 207163908U CN 201721129522 U CN201721129522 U CN 201721129522U CN 207163908 U CN207163908 U CN 207163908U
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- electric pushrod
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Abstract
The utility model discloses a kind of device of the optical maser wavelength locking for gas detection, described device includes：Laser, detector, gas absorption cell, electric pushrod and control module, wherein, the control module connects the laser, electric pushrod and detector respectively, the electric pushrod connects the gas absorption cell, the control module is when needing wavelength location to detect, control the electric pushrod action that gas absorption cell is pushed into laser to the light path between detector, and it is determined that after new laser current, control the electric pushrod that the gas absorption cell is pulled out into light path.The utility model reduce a set of laser splitting device and it is a set of refer to optical detection circuit, the light intensity of laser output can be completely used for detecting, and be advantageous to detect over long distances, cost can be also reduced with reference to the reduction of optical detection circuit.
Description
Technical field
The utility model belongs to field of gas detection, discloses a kind of dress of the optical maser wavelength locking for gas detection
Put.
Background technology
Because tunable semiconductor laser spectrum detection (TDLAS) technology has, high sensitivity, the linearity be good, detection speed
It hurry up, distance and the advantages that do not disturbed by other gases, use the instrument and equipment of tunable semiconductor laser spectrum detection technique
It is more and more.As shown in figure 1, Fig. 1 is the principle schematic using TDLAS principle light paths, the principle of TDLAS detection techniques
To utilize absorption of the gas molecule to specific wavelength spectrum, by optical maser wavelength be tuned under test gas Absorption Line on, with one
The light intensity of photo-detector monitoring laser output, when under test gas in the optical path be present, light intensity can follow gas concentration to become
Change, using lambert -- baer's law can calculate the concentration of gas.Top half is that detector 2 receives when no gas absorbs
The light intensity I arrived1, when there is gas absorption in light path, the light intensity that detector 2 receives can drop to I.According to the light intensity received
Change, the concentration of gas can be calculated.
It can be seen from above-mentioned principle, stable detection gas is realized, optical maser wavelength must be stablized, otherwise, due to laser
Influenceed output wavelength can be caused to drift about by temperature and curent change, cause gas detection inaccurate, when serious completely inspection less than.
The method for generally solving this problem is that output laser is divided into two tunnels, and detection light detects for gas all the way, another way reference
Light locks as laser output wavelength, there is the absorption cell of under test gas, reference detector moment in reference path in preset one
The position that detection gas absorb, once the adjustment that drift is carried out laser current occurs, the optical maser wavelength all-the-time stable made is in gas
Body is absorbed on position, as shown in Fig. 2 Fig. 2 is the schematic diagram of reference path and light path.In Fig. 2,1 is laser, and 2,6 are
Detector, 8, be spectroscope, 9 be speculum, and 4 be absorption cell, and 7 be spectral absorption figure.But using light splitting scheme, also bring
Following problem：
1, light splitting scheme is only applicable to time sweep, if using being to carry out spacescan, laser need to export stable straight
Stream, light splitting can not realize the purpose of Wavelength-tracking locking.
2, light-dividing device installation difficulty:Want to realize branch in original light path, it is necessary to increase a spectroscope.But spectroscope
Mounting bracket should various dimensions it is adjustable, lens angle can not be changed when having adjusted fastening again, be difficult in practical operation obtain it is good
Adjustment and fastening effect, spectroscope is big by vibration influence, and angle is easily inclined, influences the function of wavelength locking.
3, light splitting scheme to ensure length scanning precision, it is necessary to certain light intensity so that permanent in original light path
Have lost a part of intensity of light source, light source is reclaimed under poor environment in actual applications for this, signal to noise ratio can be caused to reduce, though
Length scanning locking is so realized, but sacrifices system Surveying Actual Precision.
Therefore, how to design one kind be not only suitable for time sweep be also applied for spacescan, reduce the wasting of resources, light path
The wavelength locker that stability is strong and wavelength measurement precision is high, becomes for current urgent problem to be solved.
Utility model content
The technical problems to be solved in the utility model be to overcome in the prior art be divided scheme can not application space scanning,
The wasting of resources, the problem of light path is unstable, the measuring precision is not high.
In order to solve the above technical problems, the utility model discloses a kind of dress of the optical maser wavelength locking for gas detection
Put, described device includes：Laser, detector, gas absorption cell, electric pushrod and control module, wherein, the control mould
Block connects the laser, electric pushrod and detector respectively, and the electric pushrod connects the gas absorption cell, the control
Module when needing wavelength location to detect, control electric pushrod action by gas absorption cell be pushed into laser to detector it
Between light path, and it is determined that after new laser current, control the electric pushrod to pull out the gas absorption cell and examine
Light-metering road.
Further, in addition to a display module, the laser and control module are connected, the control module controls institute
State laser and step-scan is carried out in reference current environs, per run-down, record a spatial spectral and be shown in
On the display module.
Further, the laser be arranged in parallel with detector.Certainly, can also between the laser and detector
Not parallel setting, the two also can not be in the same horizontal line.
Further, the control module is computer, tablet personal computer or other with data calculating and disposal ability
Intelligent hardware devices.
Technical solutions of the utility model, have the following advantages that：
1, the utility model solves the laser wavelength lockout issue under spacescan is applied, and the utility model is according to reality
Border is needed by the way that gas reference pond is pushed into optical path, while changes laser diode current, is carried out length scanning, is realized space
Lock function under scanning application.
2, the utility model solves the problems, such as the wasting of resources, the light source of the laser transmitting in the utility model regardless of
Light, light intensity 100% are used to survey, and also spectroscope adjustment is carried out without time and effort consuming when system is installed；Detector does not need two,
One detector is with regard to that can complete length scanning and actual measurement.
3, the utility model solves the stable problem of light path, is divided scheme additionally increased eyeglass and structural member, brings
Systematic jitters, the utility model can realize length scanning function in original light path, simplify design, improve stable
Property.
4, the utility model solves the problems, such as measurement accuracy, and scheme of the present utility model, wavelength locking and actual measurement are all
Carried out using original light path, luminous intensity is all improved both ways than prior art, so as to improve lock for sweep and measurement
Precision.
Brief description of the drawings
, below will be right in order to illustrate more clearly of the utility model embodiment or technical scheme of the prior art
The required accompanying drawing used is briefly described in embodiment or description of the prior art, it should be apparent that, describe below
In accompanying drawing be some embodiments of the present utility model, for those of ordinary skill in the art, do not paying creativeness
On the premise of work, other accompanying drawings can also be obtained according to these accompanying drawings.
Fig. 1 is the principle schematic for using TDLAS technology for detection spectrum in the prior art；
Fig. 2 is to be divided the principle schematic that scheme carries out optical maser wavelength detection in the prior art；
Fig. 3 is the structure principle chart of the device of the optical maser wavelength locking described in the utility model embodiment；
Fig. 4 is the schematic diagram of the method for the optical maser wavelength locking described in the utility model embodiment；
Fig. 5 is that the light when method locked using the optical maser wavelength described in the utility model embodiment carries out wavelength detecting is inhaled
Receive spectrogram.
Embodiment
The technical solution of the utility model is clearly and completely described below in conjunction with accompanying drawing, it is clear that described
Embodiment is the utility model part of the embodiment, rather than whole embodiments.Based on the embodiment in the utility model, sheet
The every other embodiment that field those of ordinary skill is obtained under the premise of creative work is not made, belongs to this practicality
Novel protected scope.
In the prior art, using detection of the tunable semiconductor laser spectrum detection technique to gas concentration, mainly adopt
With light splitting scheme, detection light locks for gas detection, another way reference light as laser output wavelength all the way, once compare hair
Raw wavelength output shift, then perform laser current adjustment.At present, time sweep and spacescan are divided into the scan mode of wavelength
Two ways.Time sweep, it is that same locus is scanned, light source can be changed by change over time
The mode of wavelength, obtain response of the locus to different wave length.Spacescan, it is that multiple positions in area of space are swept
Retouch, it is necessary to which the wavelength of fixed light source, the otherwise response of diverse location just do not have comparativity.It will be evident that adopt in the prior art
Light splitting scheme is only applicable to time sweep, is not suitable for spacescan, because spacescan requires the characteristic of wavelength fixation,
Light splitting scheme is not suitable for, because light splitting can not carry out whether wavelength response contrast judgement wavelength occurs drift.And existing skill
Scheme is divided in art needs two detectors, and installation is time-consuming also to cause extra increased spectroscope to cause system unstable, measures
Precision has deviation.
Shown in reference picture 3, what a kind of optical maser wavelength for gas detection disclosed in the utility model embodiment locked
Device, including：Laser 1, detector 2, gas absorption cell 3, electric pushrod 4 and control module 5, wherein, the control mould
Block 5 connects the laser 1, electric pushrod 4 and detector 2 respectively, and the laser 1 be arranged in parallel with detector 2, the control
Molding block 5 can be computer, tablet personal computer or other intelligent hardware devices with data calculating and disposal ability.It is described
The light intensity that laser 1 is sent is received by the detector 2, and light intensity is fed back to the control module 5, the control by detector 2
Module 5 to described 4 one instructions of electric pushrod, and controls the electricity when needing to carry out wavelength adjustment or wavelength location detection
Dynamic push rod 4 acts is pushed into laser 1 to the light path between detector 2 by gas absorption cell 3, meanwhile, the control module 5
Control the laser 1 to carry out step-scan, into wavelength detecting pattern, once change some electric currents per scanning space, and even
Continuous collection at least one scan period, obtained optical signal is produced into an absorption spectrogram, spectrogram is absorbed and shows on display module
Showing, display module can be integrated in control module 5, and the control module 5 determines new laser diode current according to position is absorbed,
And control the laser 1 to be adjusted to the current value newly determined, now the wavelength of laser be exactly it is desirable that measurement wavelength,
The purpose of wavelength locking is reached；After completing wavelength detecting and adjustment, the control module 5 controls electric pushrod 4 by gas again
Absorption cell 3 pulls out withdrawal from former light path, while controls laser 1 to exit wavelength detecting pattern, and package unit is according to new
Operating current enter detection.Wherein, the responsible existing computer of control principle and control algolithm on control module 5 leads to
Cross soft and hardware to combine to realize, it does not elaborate herein not where inventive point of the present utility model.
Compared with prior art, a kind of optical maser wavelength for gas detection described in the utility model embodiment locks
Device, compared to original light-dividing device, reduce a set of laser splitting device and it is a set of refer to optical detection circuit, laser output
Light intensity can be completely used for detecting, and be advantageous to detect over long distances, cost is reduced with reference to the reduction of optical detection circuit.
Coordinate shown in reference picture 4, the device to be described in detail by the present invention carries out detailed step and the side of wavelength locking below
Method.
The first step, the light source works that laser 1 is sent are sharp in equilibrium temperature and electric current, progress proper space Scanning Detction
The light intensity that light device 1 is sent is received by detector 2, and light path is formed between laser 1 and detector 2.
Second step does not stop spacescan, it is necessary to when calibrating wavelength, and control module 5 controls electric pushrod 4 to absorb gas
Pond 3 is pushed into light path.Herein, gas absorption cell 3 is also referred to as gas reference pond, and both ends optics glass capsulation is internal
Filled with calibrating gas (known gas species and concentration).Compared to original light splitting scheme, light source of the present utility model is not divided, light
Strong 100% is used to survey, and also spectroscope adjustment is carried out without time and effort consuming when system is installed；Detector does not need two, one
Detector is with regard to that can complete length scanning and actual measurement.In addition, light splitting scheme additionally increased eyeglass and structural member, bring system not
Stability, the utility model can realize length scanning function in original light path, simplify design, improve stability.
3rd step, the temperature of laser 1 is kept, change the operating current of laser 1, walked in reference current environs
Enter scanning.Reference current refer to Default Value electric current or preceding primary calibration after the current value that is preserved of computer.In this electric current
Under, just the surveyed gas of optical wavelength that laser is sent absorbs opening position.Reference current nearby refers to that reference current is certain up and down
Scope, laser wavelength deviation is corrected within this range.Step-scan refer to under reference current (on), incrementally increase and (subtract
It is small) electric current, change the optical wavelength that laser is sent.
4th step, per step-scan once, record a spatial spectral.Spatial spectral is in the display mould being connected with laser
Shown on block, it is preferred that in scanning process, inspection can be judged by the software algorithm in control module (for example being computer)
Survey whether optical path signal returns, exclude the interference of other objects in light path.There is no the interference of other objects when detecting in light path
In the case of, light path is returned in the intensity that can be maintained at certain, if the light intensity that light path returns declines to a great extent relatively, illustrates there is barrier
Hinder thing.
5th step, a position is spatially chosen, during analyzing current scanning, the Plays gas of gas absorption cell pond 3
Body draws absorption spectrogram to the absorption intensity of light intensity, absorbs spectrogram and is drawn automatically according to light intensity absorption intensity by main control computer,
Spectrogram is absorbed to be shown on display module, wherein, spectrogram is absorbed as shown in figure 5, defeated in the absorption of no gas or laser
Going out wavelength not when gas absorbs position, output is straight line, when gas absorption be present, gas absorption wavelength position light intensity
It can weaken, forming one has recessed curve, and expression is that gas absorbs position herein, and laser electricity is determined according to position is absorbed
Stream.According to foregoing known, laser specific electric current and at a temperature of, the optical wavelength sent is fixed.If wherein have one
When individual parameter changes, its optical wavelength sent can also change therewith.In normal detection process, due to the change of environment,
Laser temperature and electric current may shift, and the optical wavelength that now laser is sent may not be in the absorption position of tested gas
Put.So we need once to adjust laser at regular intervals, that is, determine laser works electric current,
So that the optical wavelength that laser is sent is just in the absorption opening position of tested gas.Pass through the side of the utility model spacescan
Method, the X-axis for absorbing spectrogram are wavelength, and Y-axis is the light intensity that light path returns, and the spectrogram shows that, when wavelength is λ 0, light intensity absorption is most
Greatly, so that it is determined that wavelength X 0 is the absorbing wavelength needed.During step by step modulating electric current, record electric corresponding to the wavelength of λ 0
Flow valuve.Preferably, due in method of the present utility model, not stopping spacescan, therefore multiple points can be spatially chosen and carried out
Spectrum analysis, multi-point average can improve the stability and accuracy of length scanning, and spacescan is that space multiple spot is swept
Retouch, the light source of diverse location, which absorbs response, difference, multi-point average to be the absorption response numerical value for choosing diverse location
Carry out calculating to average, equivalent to the calculating of one point data, improve stability.Such as：Road cross section is carried out from a left side
It is scanned to the right side, different positions difference, multi-point average may choose road surface diverse location and counted on road
Calculate.It is compared particular for the larger difference of spatial extent, can also further studies different spatial in light path
Corrected parameter (such as：Influence of the nuances such as light path, the angle of visual field to detection coefficient), for example the transverse direction in a track is swept
Retouch, when light source is in the top among track, light arrival track centre position light path is most short, the angle of visual field 0；Light reaches
Edge time journey in track is most long, and the angle of visual field is big；Due to light path and the difference of the angle of visual field, same gas concentration spectral absorption has
Difference is, it is necessary to compensate.
6th step, by the input of control module 5, laser 1 is set into the current value that previous step determines, now laser
The wavelength of device be exactly it is desirable that measurement wavelength, reached the purpose of wavelength locking.The utility model utilizes push rod by gas
Reference cell is pushed into optical path, while changes laser diode current, carries out length scanning, realizes the locking under spacescan is applied
Function.In addition, wavelength locking and actual measurement are all carried out using original light path, it is not divided, the light intensity and reality of wavelength locking
The light intensity of measurement is all higher than light splitting scheme.If with light-dividing device, the light intensity of wavelength locking is a part for light source；It is actual to survey
The light intensity of amount is except that part of loss light splitting, and also sub-fraction is absorbed by eyeglass.The utility model is substantially than existing skill
Art all improves luminous intensity both ways, so as to improve the precision of lock for sweep and measurement.
Gas absorption cell 3 is pulled out or withdrawn from light path by the 7th step, control push rod 4, makes its no longer former light path
On.
8th step, control laser 1 exits wavelength detecting pattern, and is detected according to new operating current, recovers normal empty
Between Scanning Detction.
9th step, the frequency and amplitude changed according to application environment condition is (such as:Ambient temperature, internal system temperature
Degree), timing cycle performs detection method step of the present utility model.
And the above method is applicable not only to spacescan, the detection method for time sweep is also feasible, because defeated
It is in scanning to go out laser, in that context it may be convenient to is seen with reference to absorption position.When needing position Scanning Detction, laser output is permanent
Fixed direct current, it is impossible to monitor that gas absorbs position, also substantially employ in this utility model and answered with reference to light path
Method：Timing stepping sends laser scanning signal and gas reference pond is pushed into light path, in the model of spacescan
One point position of middle selection is enclosed, once changes some electric currents per scanning space, one scan period of continuous acquisition, obtained light is believed
Number produce one absorption spectrogram, further according in this figure gas absorb position go adjust optical maser wavelength, complete to refer to backed off after random
Pond simultaneously returns to gas testing process.
Obviously, above-described embodiment is only intended to clearly illustrate example, and is not the restriction to embodiment.It is right
For those of ordinary skill in the art, can also make on the basis of the above description it is other it is various forms of change or
Change.There is no necessity and possibility to exhaust all the enbodiments.And the obvious change thus extended out or
Among the protection domain that variation is created still in the utility model.
Claims (4)
1. the device of a kind of optical maser wavelength locking for gas detection, it is characterised in that described device includes：Laser, spy
Device, gas absorption cell, electric pushrod and control module are surveyed, wherein, the control module connects the laser, electronic respectively
Push rod and detector, the electric pushrod connect the gas absorption cell, the control module when needing wavelength location to detect,
Control electric pushrod action that gas absorption cell is pushed into laser to the light path between detector, and it is determined that new
After laser current, control the electric pushrod that the gas absorption cell is pulled out into light path.
2. the device of the optical maser wavelength locking according to claim 1 for gas detection, it is characterised in that also including one
Display module, connects the laser and control module, and the control module controls laser model near reference current
Interior carry out step-scan is enclosed, per run-down, a spatial spectral is recorded and is shown on the display module.
3. the device of the optical maser wavelength locking according to claim 2 for gas detection, it is characterised in that the laser
Device be arranged in parallel with detector.
4. the device of the optical maser wavelength locking according to claim 1 for gas detection, it is characterised in that the control
Module is computer.
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| CN201721129522.7U CN207163908U (en) | 2017-09-05 | 2017-09-05 | A kind of device of optical maser wavelength locking for gas detection |
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| CN201721129522.7U CN207163908U (en) | 2017-09-05 | 2017-09-05 | A kind of device of optical maser wavelength locking for gas detection |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109596564A (en) * | 2018-10-12 | 2019-04-09 | 上海禾赛光电科技有限公司 | A kind of laser control device, array and control method |
| CN109856078A (en) * | 2019-01-16 | 2019-06-07 | 深圳供电局有限公司 | Optical gas detection system |
| 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 |
| CN111044487A (en) * | 2019-12-31 | 2020-04-21 | 绍兴市中测检测技术股份有限公司 | TDLAS technology dangerous gas leakage detection device |
-
2017
- 2017-09-05 CN CN201721129522.7U patent/CN207163908U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109596564A (en) * | 2018-10-12 | 2019-04-09 | 上海禾赛光电科技有限公司 | A kind of laser control device, array and control method |
| 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 |
| CN109856078A (en) * | 2019-01-16 | 2019-06-07 | 深圳供电局有限公司 | Optical gas detection system |
| CN111044487A (en) * | 2019-12-31 | 2020-04-21 | 绍兴市中测检测技术股份有限公司 | TDLAS technology dangerous gas leakage detection device |
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