Oil stain detector based on laser-induced fluorescence

Abstract

The utility model relates to the field of oil stain detectors, in particular to an oil stain detector based on laser-induced fluorescence. The oil stain detector comprises an amplifier, a microcontroller, a laser tube, a first collimating lens, a first optical filter, a reflector, a photoelectric detector, a second collimating lens, a second optical filter, a dichroscope and a shell, and the laser tube, the first collimating lens, the first optical filter and the reflector are sequentially arranged in a first vertical channel from top to bottom. A photoelectric detector, a second collimating lens, a second optical filter and a dichroscope are sequentially arranged in the second vertical channel from top to bottom, the first vertical channel and the second vertical channel are communicated through a connecting channel, the connecting channel is located between the reflector and the dichroscope, and the laser tube, the photoelectric detector and the amplifier are all electrically connected to the microcontroller. According to the device, laser is used for inducing fluorescence, emitted fluorescence can be accurately detected, whether oil stains exist on the surface of a component or not is judged, and detection can be carried out in the environment without complete light shielding.

Description

Technical Field

[0001] The utility model relates to the field of oil stain detectors, especially an oil stain detector based on laser-induced fluorescence. Background Technique

[0002] In today's mechanical manufacturing industry, silicone oil, mineral oil, and vegetable oil have become essential processing materials in industrial production. These materials are used on various types of machinery to reduce friction and protect the machinery and processed parts as liquid lubricants, mainly playing roles such as controlling friction, reducing wear, cooling, and sealing isolation. However, during the processing, oil stains will splash to other places. Oil stains will increase the incidence of fires and pose safety hazards. For example, if the oil stains in a gas station or oil depot area are not cleaned in time, they are likely to cause a fire when encountering an open flame or high temperature, and the fire will spread rapidly, increasing the difficulty and danger of fire fighting. In addition, the presence of oil stains will also affect the process. For example, in ultrasonic welding, it will affect the welding quality and effect, and then lead to circuit failures and even potential safety hazards; in an automobile production line, if there are oil stains on the mechanical equipment, it may cause equipment failures or shutdowns for maintenance, which will not only delay the production cycle but also increase the maintenance cost; during the aircraft maintenance process, if there are oil stains on the fuselage or components, it will increase the working time and difficulty of maintenance personnel and even affect flight safety.

[0003] In recent years, most of the research on oil stain detectors has been on the detection methods of engine oil and vegetable oil. In 2018, the Institute of Optoelectronic Imaging and Information Engineering, School of Optoelectronics, Beijing Institute of Technology proposed a rapid identification method for common engine oil based on laser-induced fluorescence [Spectroscopy and Spectral Analysis, 2014, 34(08): 2148-2151]; in 2014, the Huizhou Quality and Metrology Supervision and Inspection Institute in Guangdong Province carried out research on the fluorescence spectral analysis of 8 kinds of edible vegetable oils [Science and Technology of Food Industry, 2014, 35(14): 64-67]. The above work can only be carried out under laboratory conditions using instruments such as spectrometers and molecular fluorescence photometers in a completely light-shielded environment, which has great limitations and does not have wide applicability. Content of the Utility Model

[0004] The technical problem to be solved by the utility model is: to solve the technical problems described in the background technique, the utility model provides an oil stain detector based on laser-induced fluorescence. By using laser-induced fluorescence, the emitted fluorescence can be accurately detected, and then it can be judged whether there is an oil stain on the surface of the component, and the detection can be carried out in an environment that does not require complete light shielding.

[0005] The technical solution adopted by the utility model to solve its technical problems is:

[0006] An oil pollution detector based on laser-induced fluorescence, comprising an amplifier, a microcontroller, a laser tube, a first collimating lens, a first filter, a reflector, a photodetector, a second collimating lens, a second filter, a dichroic mirror, and a housing. A first vertical channel and a second vertical channel are provided inside the housing. Inside the first vertical channel, the laser tube, the first collimating lens, the first filter, and the reflector are successively arranged from top to bottom. Inside the second vertical channel, the photodetector, the second collimating lens, the second filter, and the dichroic mirror are successively arranged from top to bottom. The first vertical channel and the second vertical channel are connected through a connecting channel, and the connecting channel is located between the reflector and the dichroic mirror. The laser tube, the photodetector, and the amplifier are all electrically connected to the microcontroller, and an opening is provided at the bottom of the second vertical channel.

[0007] Specifically, the microcontroller includes a signal source, a phase shifter, a mixer, and a low-pass filter. The low-pass filter is electrically connected to the amplifier, the photodetector is electrically connected to the mixer, and the laser tube is electrically connected to the signal source.

[0008] Specifically, the laser tube is a 375nm laser tube.

[0009] Specifically, the first filter is a 375nm optical narrow-band filter.

[0010] Specifically, the second filter is a 420nm optical narrow-band filter.

[0011] Specifically, the microcontroller is electrically connected to a display screen.

[0012] Specifically, the microcontroller is electrically connected to a buzzer.

[0013] Specifically, the microcontroller is electrically connected to a host computer.

[0014] The beneficial effects of the present utility model are as follows: The present utility model provides an oil pollution detector based on laser-induced fluorescence. By using laser-induced fluorescence, the emitted fluorescence can be accurately detected, thereby determining whether there is oil pollution on the surface of the component, and it can be detected in an environment that does not require complete light shielding. Description of the Drawings

[0015] The present utility model will be further described below in conjunction with the drawings and embodiments.

[0016] Figure 1 is the structural block diagram of the present utility model;

[0017] Figure 2 is the structural schematic diagram of the present utility model;

[0018] Figure 3 is the structural schematic diagram of the housing of the present utility model and the optical elements inside the housing;

[0019] In the figure, 1. amplifier, 2. microcontroller, 3. laser tube, 4. first collimating lens, 5. first filter, 6.

[0020] reflecting mirror, 7. photodetector, 8. second collimating lens, 9. second filter, 10. dichroic mirror, 11. housing, 12. first vertical channel, 13. second vertical channel, 21. signal source, 22. phase shifter, 23.

[0021] mixer, 24. low-pass filter. Detailed implementation mode

[0022] Now, the present utility model will be further described in detail with reference to the accompanying drawings. These drawings are all simplified schematic diagrams, only illustrating the basic structure of the present utility model in a schematic manner, so they only show the components related to the present utility model.

[0023] Figure 1 It is the structural block diagram of the present utility model; Figure 2 It is the structural schematic diagram of the present utility model; Figure 3 It is the present

[0024] structural schematic diagram of the housing of the utility model and the optical elements inside the housing.

[0025] Combined with Figure 1 , Figure 2 and Figure 3 shown in the figure, an oil stain detector based on laser-induced fluorescence includes an amplifier 1, a microcontroller 2, a laser tube 3, a first collimating lens 4, a first filter 5, a reflecting mirror 6, a photodetector 7, a second collimating lens 8, a second filter 9, a dichroic mirror 10, and a housing 11. A first vertical channel 12 and a second vertical channel 13 are provided inside the housing 11. Inside the first vertical channel 12, a laser tube 3, a first collimating lens 4, a first filter 5, and a reflecting mirror 6 are successively arranged from top to bottom. Inside the second vertical channel 13, a photodetector 7, a second collimating lens 8, a second filter 9, and a dichroic mirror 10 are successively arranged from top to bottom. The first vertical channel 12 and the second vertical channel 13 are connected and communicated through a connection channel, and the connection channel is located between the reflecting mirror 6 and the dichroic mirror 10. The laser tube 3, the photodetector 7, and the amplifier 1 are all electrically connected to the microcontroller 2, and an opening is provided at the bottom of the second vertical channel 13.

[0026] The microcontroller 2 includes a signal source 21, a phase shifter 22, a mixer 23, and a low-pass filter 24. The low-pass filter 24 is electrically connected to the amplifier 1, the photodetector 7 is electrically connected to the mixer 23, and the laser tube 3 is electrically connected to the signal source 21.

[0027] The laser tube 3 is a 375nm laser tube.

[0028] The first filter 5 is a 375nm optical narrowband filter.

[0029] The second filter 9 is a 420nm optical narrow-band filter.

[0030] Both silicone oil and engine oil have peaks at a wavelength of 420nm, so 420nm is selected as the wavelength for detecting fluorescence.

[0031] The microcontroller 2 is electrically connected to the display screen.

[0032] The microcontroller 2 is electrically connected to the buzzer.

[0033] The microcontroller 2 is electrically connected to the host computer.

[0034] The light emitted by the laser tube 3 with a wavelength of 375nm is collimated by the first collimating lens 4, and then passes through the first 375nm optical narrow-band filter 5 to make the 375nm light emitted by the laser tube 3 purer in terms of wavelength. Then it is reflected to the surface of the sample to be measured through the mirror 6 and the dichroic mirror 10. When the light with a wavelength of 375nm hits the sample surface and induces fluorescence, the generated light passes through the dichroic mirror 10 and then through the second 420nm optical narrow-band filter 9 to filter out the 375nm light that reaches here due to reflection. The light that passes through is the fluorescence signal induced by the laser. It is converged by the second collimating lens 8 and finally reaches the photodetector 7 to obtain an oil stain signal in the form of voltage. The scanning signal generated by the microcontroller 2 (Microcontroller Unit, MCU) is added to the modulation signal to drive the laser tube 3. The fluorescence signal in the form of voltage generated by the photodetector 7 and the signal generated by the phase shifter 22 enter the mixer 23.

[0035] The DAC function of the microcontroller 2 generates a scanning signal and a sine wave signal. The low-frequency scanning signal is used as a current signal, and the high-frequency sine signal is used as a wavelength modulation signal. The signal after adding the two is used to drive the laser tube 3. The frequency of the sine signal is much higher than that of the scanning signal, which can further improve the signal-to-noise ratio. The photodetector 7 collects the fluorescence signal induced by the laser. Regarding demodulation, the present application uses second-harmonic demodulation. Using the DAC function of the microcontroller 2, a second-harmonic signal of the modulation signal is generated. After this signal enters the phase shifter 22, it performs a multiplication operation with the fluorescence signal in the mixer 23. The generated mixed-frequency signal is sent to the low-pass filter 24 to filter out all high-frequency terms related to time, adjust the phase so that the demodulated signal is the maximum value, and the second derivative of the fluorescence signal with a relatively high signal-to-noise ratio can be obtained, that is, the effective information of the fluorescence signal is obtained. Then this signal is amplified by the amplifier 1. By this modulation and demodulation method, the signal-to-noise ratio is improved, so that detection can be performed in an environment that is not completely light-shielded.

[0036] Inspired by the above-described ideal embodiments of the present utility model, through the above description, relevant staff can completely make various changes and modifications without departing from the technical idea of this utility model. The technical scope of this utility model is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. An oil pollution detector based on laser induced fluorescence, characterized in that: The invention comprises an amplifier (1), a microcontroller (2), a laser tube (3), a collimating lens (4), a filter (5), a reflector (6), a photodetector (7), a collimating lens (8), a filter (9), a dichroic mirror (10), and a housing (11). A vertical channel (12) and a vertical channel (13) are arranged in the housing (11). The vertical channel (12) is provided with a laser tube (3), a collimating lens (4), a filter (5), a reflector (6), a photodetector (7), a collimating lens (8), a filter (9), a dichroic mirror (10), and a housing (11). A reflector (6) is provided in the vertical channel (13), and a photodetector (7), a collimating lens (8), a filter (9), and a dichroic mirror (10) are arranged in sequence from top to bottom. The vertical channel (12) and the vertical channel (13) are connected through a connecting channel, and the connecting channel is located between the reflector (6) and the dichroic mirror (10). The laser tube (3), the photodetector (7), and the amplifier (1) are all electrically connected to the microcontroller (2). An opening is provided at the bottom of the vertical channel (13).

2. The oil pollution detector based on laser induced fluorescence according to claim 1 is characterized in that: The microcontroller (2) comprises a signal source (21), a phase shifter (22), a mixer (23), and a low-pass filter (24); the low-pass filter (24) is electrically connected to the amplifier (1); the photodetector (7) is electrically connected to the mixer (23); and the laser tube (3) is electrically connected to the signal source (21).

3. The oil pollution detector based on laser induced fluorescence according to claim 1 is characterized in that: The laser tube (3) is a 375nm laser tube.

4. The oil pollution detector based on laser induced fluorescence according to claim 1 is characterized in that: The filter one (5) is a 375nm optical narrowband filter.

5. The oil pollution detector based on laser induced fluorescence according to claim 1 is characterized in that: The second filter (9) is a 420nm optical narrowband filter.

6. The oil pollution detector based on laser induced fluorescence according to claim 1 is characterized in that: The microcontroller (2) is electrically connected to the display screen.

7. The oil pollution detector based on laser induced fluorescence according to claim 1 is characterized in that: The microcontroller (2) is electrically connected to the buzzer.

8. The oil pollution detector based on laser induced fluorescence according to claim 1 is characterized in that: The microcontroller (2) is electrically connected to a host computer.

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