CN209513532U - A kind of laser dust monitor that dark current automatically removes - Google Patents
A kind of laser dust monitor that dark current automatically removes Download PDFInfo
- Publication number
- CN209513532U CN209513532U CN201920260055.4U CN201920260055U CN209513532U CN 209513532 U CN209513532 U CN 209513532U CN 201920260055 U CN201920260055 U CN 201920260055U CN 209513532 U CN209513532 U CN 209513532U
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- China
- Prior art keywords
- laser
- circuit
- output
- dark current
- dust monitor
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- Expired - Fee Related
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Abstract
A kind of laser dust monitor that dark current automatically removes, including laser tube, permanent optical power driving circuit, oscillating circuit, PIN diode, I-V conversion circuit, voltage amplifier circuit, analog switch, low-pass filter and signal acquisition process display circuit.Oscillating circuit generates the square-wave signal that duty ratio is 50%, controls permanent optical power driving circuit and drives laser tube periodical launch laser；The polarity that analog switch switching receives signal is controlled simultaneously, to realize the automatic elimination of dark current.The utility model automatically removes circuit by dark current, eliminates measurement error brought by the variation of the dark current due to caused by the operation conditions changes such as operating temperature, operating voltage, ensure that the precision of laser dust monitor measurement；Dark current variation bring measurement error caused by photodiode performance caused by working long hours changes is also eliminated, the service life of laser dust monitor is extended；Keep the precision of laser dust monitor higher, stability is more preferable, and the service life is longer.
Description
Technical field
The utility model relates to dust monitoring field more particularly to a kind of laser dust monitors that dark current automatically removes.
Background technique
Dust is a kind of solid particle that can be present in a manner of swimming for a long time in air.Dust will lead to lung's disease
A variety of diseases such as disease, skin infection, cancer, seriously affect the health of people.Dust outside discharge workshop can also pollute factory
Environment outside area impacts the residents ' health around plant area, impacts to the production of agriculture, woods, animal husbandry.This several years air
For contamination phenomenon than more serious, the pollution of dust is also a critically important factor.Requirement with people to production, living environment
Higher and higher, people also increasingly pay attention to environmental protection.The monitoring and control of dust is also increasingly taken seriously.
Dust detector is exactly the special instrument for detecting dust in air concentration.In practical applications, common powder
There are three types of dirt detection method is usual: weight method, laser method and actinobolia.
Laser method measures dust concentration by decaying of the measurement laser after the tested air comprising dust or scattering.
Dust concentration is higher, and decaying and scattering are stronger.
Existing laser dust monitor mostly uses greatly Continuous Drive mode, inevitably there is dark current with work temperature
Degree, operating voltage fluctuation and the problem of change.With the increase of working time, the photodiode performance of reception becomes
Change the increase for also bringing along dark current, increases so as to cause the error of measurement result.
The influence of dark current how is reduced, to reduce measurement error, extends dust instrument service life, is current laser powder
One of dirt instrument problem to be solved.
Summary of the invention
The utility model aim is for defect existing for existing laser dust monitor, provides a kind of dark current and automatically removes
Laser dust monitor extend dust instrument service life to reduce measurement error.
The utility model to achieve the above object, adopts the following technical scheme that
A kind of laser dust monitor that dark current automatically removes, including laser tube and for receiving the laser tube emissions laser
Reception device；It is characterized by:
The reception device output connection I-V conversion circuit, is converted to voltage signal for output current signal；
The I-V conversion circuit output connection voltage amplifier circuit, the voltage signal of output is amplified；
The voltage amplifier circuit output while the positive input terminal and negative input end for connecting an analog switch；
The analog switch connects an oscillating circuit, controls the analog switch by the output of the oscillating circuit
Positive input terminal is connected with negative input end；The analog switch output connection low-pass filter；
The low-pass filter exports connection signal acquisition process display circuit；
For the signal acquisition process display circuit for acquiring the low-pass filter output signal, output display dust is dense
Degree；
The oscillating circuit connects permanent optical power driving circuit simultaneously, controls the permanent optical power driving by oscillator signal
Circuit output；
The perseverance optical power driving circuit output connects the laser tube, makes the laser tube periodical launch laser.
It is further characterized by: the oscillating circuit exports square wave.
Preferred: the square wave is the square wave of duty ratio 50%.
The laser tube is the laser diode of wavelength 650nm maximum power 10mW；The oscillating circuit uses NE555 collection
It is built at chip；The reception device is S1226-44BK PIN diode；The analog switch is CD4053 chip；It is described low
Bandpass filter is capacitance-resistance filter.
The utility model controls laser tube periodical launch laser and simulation by oscillating circuit outputting oscillation signal simultaneously
Switching, so that dark current and normal current signal are superimposed on low-pass filter, to counteract the influence of dark current.Subtract
It is small due to operating temperature, operating voltage fluctuation and cause dark current change caused by measurement error；Simultaneously reduce due to it is long when
Between work caused by measurement error caused by reception reception device performance change, to extend the service life of dust instrument.
Detailed description of the invention
Fig. 1 is the utility model principle schematic diagram.
Specific embodiment
As shown in Figure 1, a kind of laser dust monitor that dark current automatically removes, including laser tube 1 and for receiving laser tube 1
Emit the PIN diode 23 of laser.
The output connection I-V conversion circuit 24 of PIN diode 23, is converted to voltage signal for output current signal.
The output connection voltage amplifier circuit 25 of I-V conversion circuit 24, the voltage signal of output is amplified.
The output of voltage amplifier circuit 25 while the positive input terminal and negative input end for connecting an analog switch 26.
Analog switch 26 connects an oscillating circuit 22, is opened by the square-wave signal control simulation of the output of oscillating circuit 22
The positive input terminal for closing 26 is connected with negative input end；Output one low-pass filter 27 of connection of analog switch 26.
Low-pass filter 27 exports connection signal acquisition process display circuit 28.
Signal acquisition process display circuit 28 is for acquiring 27 output signal of low-pass filter, output display dust concentration.
Oscillating circuit 22 connects permanent optical power driving circuit 21 simultaneously, controls permanent optical power driving circuit by square-wave signal
21 outputs.
The permanent output of optical power driving circuit 21 connection laser tube 1, makes 1 periodical launch laser of laser tube.
Preferred: laser tube 1 uses the laser diode of wavelength 650nm maximum power 10mW.Oscillating circuit 22 can be used
NE555 integrated chip is built.PIN diode 23 uses S1226-44BK.CD4053 chip can be used to realize for analog switch 26.It is low
Capacitance-resistance filter can be used to realize for bandpass filter 27.Square-wave signal is the square wave of duty ratio 50%.
When utility model works, oscillating circuit 22 generates the square-wave signal that duty ratio is 50%, closes in low level permanent
Optical power driving circuit 21, laser tube 1 does not emit laser, while analog switch 26 is switched to negative output terminal.PIN diode at this time
23 do not receive light, and the dark current signals of PIN diode 23 export after I-V conversion circuit 24 and voltage amplifier circuit 25,
This dark current signals reversely accesses low-pass filter 27.Permanent optical power driving circuit 21 is opened in high level, laser tube 1 emits
Laser, while analog switch 26 is switched to positive output end.At this time PIN diode 23 receive scattering light, PIN diode 23 it is normal
Current signal exports after I-V conversion circuit 24 and voltage amplifier circuit 25, this normal current signal forward direction accesses low pass filtered
Wave device 27.It is superimposed on low-pass filter 27 by toggling dark current and normal current signal, to counteract dark current
Influence.
Claims (4)
1. a kind of laser dust monitor that dark current automatically removes, including laser tube and for receiving the laser tube emissions laser
Reception device；It is characterized by:
The reception device output connection I-V conversion circuit, is converted to voltage signal for output current signal；
The I-V conversion circuit output connection voltage amplifier circuit, the voltage signal of output is amplified；
The voltage amplifier circuit output while the positive input terminal and negative input end for connecting an analog switch；
The analog switch connects an oscillating circuit, controls the just defeated of the analog switch by the output of the oscillating circuit
Enter end to connect with negative input end；The analog switch output connection low-pass filter；
The low-pass filter exports connection signal acquisition process display circuit；
The signal acquisition process display circuit is for acquiring the low-pass filter output signal, output display dust concentration；
The oscillating circuit connects permanent optical power driving circuit simultaneously, controls the permanent optical power driving circuit by oscillator signal
Output；
The perseverance optical power driving circuit output connects the laser tube, makes the laser tube periodical launch laser.
2. the laser dust monitor that dark current as described in claim 1 automatically removes, it is characterised in that: the oscillating circuit output
Square wave.
3. the laser dust monitor that dark current as claimed in claim 2 automatically removes, it is characterised in that: the square wave is duty ratio
50% square wave.
4. the laser dust monitor that dark current as described in any one of claims 1-3 automatically removes, it is characterised in that: the laser
Pipe is the laser diode of wavelength 650nm maximum power 10mW；The oscillating circuit is built using NE555 integrated chip；It is described
Reception device is S1226-44BK PIN diode；The analog switch is CD4053 chip；The low-pass filter is capacitance-resistance
Filter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920260055.4U CN209513532U (en) | 2019-03-01 | 2019-03-01 | A kind of laser dust monitor that dark current automatically removes |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920260055.4U CN209513532U (en) | 2019-03-01 | 2019-03-01 | A kind of laser dust monitor that dark current automatically removes |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN209513532U true CN209513532U (en) | 2019-10-18 |
Family
ID=68204922
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201920260055.4U Expired - Fee Related CN209513532U (en) | 2019-03-01 | 2019-03-01 | A kind of laser dust monitor that dark current automatically removes |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN209513532U (en) |
-
2019
- 2019-03-01 CN CN201920260055.4U patent/CN209513532U/en not_active Expired - Fee Related
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20191018 Termination date: 20200301 |